Convert :vector to library and introduce new a application module

[ouchadam]

By converting :vector to a library we'll be able to quickly introduce new modules by depending on :vector

We'll introduce a new :vector-app module, name TBC, to be our android application module containing signing configuration, dagger entry point and VectorApplication class

TBD if we want to lift the variants and build types out of the library and only expose them as part of the application module (this has the benefit of making the :vector module cacheable and reusable across variants, speeding up CI build times)

[ouchadam]

Fixed by #6720 in 1.4.36