[bazel] Add initial docs for bazel use (and .bazelrc tips)

Change-Id: I6da8f5ad6e172d01a451607ac01693407aced858
Bug: skia:12541
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/534976
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
1 file changed