This add a workflow which is a wrapper to the cmake/ninja build.
This will later be used as a preliminary step to `arc unit`.
Arguments (all are optional):
- `--dir=<build_dir>`: set the build directory (absolute or relative
to project root).
- `--clear-cache`: force CMake to rebuild the cache.
- `--post-clean`: delete the build directory after a successful build.
- `targets`: specify which Ninja target to build.