[EZ][Refactor][Gradle] Use secrets plugin and some cleanup.

[itissid]

To use this PR, in your local.properties file add the following line :

MAPS_API_KEY='XXXXXXXXXXXXXXXX'

No need to hard code the API_KEY in your manifest. Lets use the secrets plugin to set the requisite key locally and build. per https://developers.google.com/maps/documentation/android-sdk/config

Additionally https://docs.gradle.org/current/userguide/plugins.html#sec:plugin_management and https://docs.gradle.org/current/userguide/dependency_management.html#sub:centralized-repository-declaration recommend centralizing the deps and plugin management which I chanced upon in google's instructions when I was using the secrets plugin; So I cleaned up those as well.

[itissid]

Maps access works:

[itissid]

Noob Question: I merged origin/main from this project into mine before pushing, but it created an extra merge commit. I think some people hate that and like that we rebase the branch on master before making the PR.

Do you have a preference?