[VOL-5114] - bbsim version is stale

Makefile
.gitignore
makefiles/lint/helm/include.mk
makefiles/lint/helm/helmrepo.mk
-------------------------------
  o Added convenience targets for cloning cord-charts-repo
  o helmrepo.mk added for interactive use so devs working
    locally can run the same code checks as jenkins commit hook.

bbsim/Chart.yaml
----------------
   o Bump bbsim version, very stale (1.12.10 VS 1.15.2).
     https://github.com/opencord/bbsim/releases/tag/v1.15.2
     A new bbsim release build needed but get current first.
   o Bump version string as well, helm checks report 4.8.9
     already exists.
   o Another failure wrt duplicate voltha-stack was reported
     but get this patch in first for current status from jenkins
     then deal with downstream failures as git commit --amend.

Change-Id: I8320f75ad48de02986d32e391b429e0ea4375b2b
diff --git a/.gitignore b/.gitignore
index 27fdd02..ba31c93 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+# -*- makefile -*-
+
 # local chart repo dir used when building the http-accessible repo
 chart_repo
 
@@ -14,12 +16,20 @@
 # should be working in a temp dir -vs- (read-only) checkout dir.
 tagcollisionreject.tmp.sh
 
-# helm-repo-tools is cloned in the Makefile if not present
+# ---------------------------
+# Repositories cloned locally
+# ---------------------------
+cord-charts-repo/
 helm-repo-tools/
 
+# ----------
 # misc files
+# ----------
 .*.swp
+*~
 .remote-sync.json
 .DS_Store
 #Idea
 .idea/
+
+# [EOF]