Moving to go mod and improving the build

Change-Id: I9089656aae6313b0d5576fdb6de411d8301114d8
diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..685fc84
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,3 @@
+voltha-bbsim_*
+.gitignore
+.gitreview
\ No newline at end of file