[components] Added features to support application-services branch builds

[components] Added features to support application-services branch builds

Added support for branch-build settings in `local.properties`:
  - If `branchBuild.android-components.version` is set, then we
    set the android-components version to that exact string.

  - If `branchBuild.application-services.dir` is set, then run
    `build-scripts/substitute-local-appservices.gradle` script, like we
    do with `autoPublish`.  However, in this case, that script expects
    the app-services packages to be be built ahead of time with a
    specific version name specified by
    `branchBuild.application-services.version`.

  - Added support for the absolute paths when running the substutition
    scripts.

  - Updated `substitute-local-ac.gradle` to check the
    `localProperties.branchBuild.android-components.version`.

The plan is to use this feature to build/test fenix using a particular
checkout of application-services and androd-components, with the
versions set to the git commit ID.