feat(API): Expose androidProcessService - getAppProcessId

[rosen-vladimirov]

Expose the getAppProcessId method from androidProcessService, so it can be called when using CLI as a library.

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/nativescript-cli/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
• Tests for the changes are included.

NOTE: Merge after telerik/mobile-cli-lib#1086

[Fatme]

run ci

[dtopuzov]

run ci