[vet] Make implicit dep detection more accurate

[variants] Support component-level exclusion

whereby excluded components are simply not present and all dependencies
to their packages are silently removed.

[fmt] Sort dependencies ascending

Add global dont-test command-line flag

Using `--dont-test` one can now disable package-level tests. The effect
is the same as if one were to set `dontTest` on all packages. Using this
flag does not affect a packages version.

Add squash option to Docker package builds

[werft] Added werft compatible reporter

[breaking] WORKSPACE and BUILD are now WORKSPACE.yaml and BUILD.yaml

[bugfix] Include full BUILD file in version, not arg resolved config

Config changes, improved version computation and build area synthesis

- typescript packages: library config field is replaced with "packaging"
- go packages: library config field is replaced with "packaging"
Thanks @AlexTugarev for the suggestion

- packages no longer depend on the whole build file but just their own config
- safer naming convention for linked dependencies in the build area

Initial commit