basic bazel project structure

Express skcms' project structure in Bazel.

bazel build ... and bazel test ... work for me on WSL2 Ubuntu 20.04.

Everything was reassuringly sandboxed by default:
    - tests binary needed our profiles/ directory declared as
      a data dependency when run under bazel test
    - visibility all defaulted to something locked down,
      I think "visible to targets declared in this BUILD file"
    - (not in this CL) to build with ccache, I had to set in .bazelrc
      `build --sandbox_writable_path=/home/mtklein/.ccache`

buildifier seems to work ok for formatting.
(go get github.com/bazelbuild/buildtools/buildifier)

Change-Id: I70d0de71ef91dbfd8bb2e3d0700c2df125cb4f7f
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/304849
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
4 files changed