Allow selecting individual outputs from a rule

[DolceTriade]

If one wants to select a single output from a build (like a single shared library or a single static library), it's not possible to do so with the current code. The current code only creates an output_group for the declared binaries, which isn't sufficient.

This change creates an output group for all the artifacts including the includes.

Fixes #768

[DolceTriade]

bazel build --show_progress_rate_limit=5 --curses=yes --color=yes --terminal_columns=143 --show_timestamps --verbose_failures --jobs=30 --announce_rc --experimental_repository_cache_hardlinks --disk_cache= --sandbox_tmpfs_path=/tmp --google_default_credentials --remote_cache=remotebuildexecution.googleapis.com --remote_instance_name=projects/bazel-untrusted/instances/default_instance --bes_backend=buildeventservice.googleapis.com --bes_timeout=360s --bes_instance_name=bazel-untrusted --remote_timeout=60 --remote_max_connections=200 --remote_default_platform_properties=properties:{name:"cache-silo-key" value:"f715d4f7e3ad3942ee54f8cd9a9ed93f7808f63c82bbf62d6628653f83f874fa"} --remote_download_toplevel --experimental_enable_aggregating_middleman=False --test_env=HOME --test_env=BAZELISK_USER_AGENT --test_env=USE_BAZEL_VERSION -- //... -//cmake_android:app
--
  | ERROR: --bes_instance_name=bazel-untrusted :: Unrecognized option: --bes_instance_name=bazel-untrusted
  | INFO: Invocation ID: 72a67d79-be10-457d-a3f8-556cbf632730
  | bazel build failed with exit code 2
  | 🚨 Error: The command exited with status 1
  | user command error: The plugin docker command hook exited with status 1

Seems like the CI is broken unrelated to this change?

[jsharpe]

LGTM, thanks!