[VOL-3860] redis client support in voltha-lib-go

redis client support has been added in this patch. There are two
types client `redis` and `redis-sentinel` to connect a redis instance.
redis-sentinel is required to be able to find the master redis
instance from a redis-sentinel process. See redis-sentinel usage
https://redis.io/topics/sentinel and
https://pkg.go.dev/github.com/go-redis/redis/v8#NewFailoverClient
for more information. If there is no need to have any failover
mechanism then the redis client type is the option to choose.

Change-Id: I997ed92115a9d565df632c6dd8184b9bab77b991
diff --git a/vendor/github.com/go-redis/redis/v8/result.go b/vendor/github.com/go-redis/redis/v8/result.go
new file mode 100644
index 0000000..24cfd49
--- /dev/null
+++ b/vendor/github.com/go-redis/redis/v8/result.go
@@ -0,0 +1,180 @@
+package redis
+
+import "time"
+
+// NewCmdResult returns a Cmd initialised with val and err for testing.
+func NewCmdResult(val interface{}, err error) *Cmd {
+	var cmd Cmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewSliceResult returns a SliceCmd initialised with val and err for testing.
+func NewSliceResult(val []interface{}, err error) *SliceCmd {
+	var cmd SliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewStatusResult returns a StatusCmd initialised with val and err for testing.
+func NewStatusResult(val string, err error) *StatusCmd {
+	var cmd StatusCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewIntResult returns an IntCmd initialised with val and err for testing.
+func NewIntResult(val int64, err error) *IntCmd {
+	var cmd IntCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewDurationResult returns a DurationCmd initialised with val and err for testing.
+func NewDurationResult(val time.Duration, err error) *DurationCmd {
+	var cmd DurationCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewBoolResult returns a BoolCmd initialised with val and err for testing.
+func NewBoolResult(val bool, err error) *BoolCmd {
+	var cmd BoolCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewStringResult returns a StringCmd initialised with val and err for testing.
+func NewStringResult(val string, err error) *StringCmd {
+	var cmd StringCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewFloatResult returns a FloatCmd initialised with val and err for testing.
+func NewFloatResult(val float64, err error) *FloatCmd {
+	var cmd FloatCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewStringSliceResult returns a StringSliceCmd initialised with val and err for testing.
+func NewStringSliceResult(val []string, err error) *StringSliceCmd {
+	var cmd StringSliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewBoolSliceResult returns a BoolSliceCmd initialised with val and err for testing.
+func NewBoolSliceResult(val []bool, err error) *BoolSliceCmd {
+	var cmd BoolSliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewStringStringMapResult returns a StringStringMapCmd initialised with val and err for testing.
+func NewStringStringMapResult(val map[string]string, err error) *StringStringMapCmd {
+	var cmd StringStringMapCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewStringIntMapCmdResult returns a StringIntMapCmd initialised with val and err for testing.
+func NewStringIntMapCmdResult(val map[string]int64, err error) *StringIntMapCmd {
+	var cmd StringIntMapCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewTimeCmdResult returns a TimeCmd initialised with val and err for testing.
+func NewTimeCmdResult(val time.Time, err error) *TimeCmd {
+	var cmd TimeCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewZSliceCmdResult returns a ZSliceCmd initialised with val and err for testing.
+func NewZSliceCmdResult(val []Z, err error) *ZSliceCmd {
+	var cmd ZSliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewZWithKeyCmdResult returns a NewZWithKeyCmd initialised with val and err for testing.
+func NewZWithKeyCmdResult(val *ZWithKey, err error) *ZWithKeyCmd {
+	var cmd ZWithKeyCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewScanCmdResult returns a ScanCmd initialised with val and err for testing.
+func NewScanCmdResult(keys []string, cursor uint64, err error) *ScanCmd {
+	var cmd ScanCmd
+	cmd.page = keys
+	cmd.cursor = cursor
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewClusterSlotsCmdResult returns a ClusterSlotsCmd initialised with val and err for testing.
+func NewClusterSlotsCmdResult(val []ClusterSlot, err error) *ClusterSlotsCmd {
+	var cmd ClusterSlotsCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewGeoLocationCmdResult returns a GeoLocationCmd initialised with val and err for testing.
+func NewGeoLocationCmdResult(val []GeoLocation, err error) *GeoLocationCmd {
+	var cmd GeoLocationCmd
+	cmd.locations = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewGeoPosCmdResult returns a GeoPosCmd initialised with val and err for testing.
+func NewGeoPosCmdResult(val []*GeoPos, err error) *GeoPosCmd {
+	var cmd GeoPosCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewCommandsInfoCmdResult returns a CommandsInfoCmd initialised with val and err for testing.
+func NewCommandsInfoCmdResult(val map[string]*CommandInfo, err error) *CommandsInfoCmd {
+	var cmd CommandsInfoCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewXMessageSliceCmdResult returns a XMessageSliceCmd initialised with val and err for testing.
+func NewXMessageSliceCmdResult(val []XMessage, err error) *XMessageSliceCmd {
+	var cmd XMessageSliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}
+
+// NewXStreamSliceCmdResult returns a XStreamSliceCmd initialised with val and err for testing.
+func NewXStreamSliceCmdResult(val []XStream, err error) *XStreamSliceCmd {
+	var cmd XStreamSliceCmd
+	cmd.val = val
+	cmd.SetErr(err)
+	return &cmd
+}