Disable bazel build for gcc 4.8, upgrade versions for grpc and bazel, document bazel support

[lalitb]

Fixes #947

Changes

• Disable bazel build for gcc4.8, and this allows us to upgrade grpc and bazel versions used for the bazel build
• Document build type supported for all platforms in README.md
• Document Bazel build as experimental ( till it is supported for all the components) in INSTALL.md
• macOS build is failing with the latest bazel version, have added a temporary fix for that for now.

New versions:
grpc : 1.39.1
Bazel: 4.2.0
Bazelisk: 1.10.1

cc @jsuereth

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #953 (4d04d7a) into main (5e4962d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #953   +/-   ##
=======================================
  Coverage   95.36%   95.36%           
=======================================
  Files         160      160           
  Lines        6780     6780           
=======================================
  Hits         6465     6465           
  Misses        315      315           

[jsuereth]

I'd say just remove this instead of comment. It's unlikely we can bring it back and of we need it it's in git history.