Move BuildConfig fields to vector-configs module

[giomfo]

Element avoids the direct usage of BuildConfig fields since the version v1.4.32 (related PR)
The goal of this request is to do the same for Tchap by moving all the build configs and resource configs to the dedicated module vector-configs.

Doing that, we have more flexibility to override some config in the unit tests and centralize it in a single place (making it easier to track)

Note: a PR has been already started :#717