Renaming the App

[gary-kim]

In the interest of adding more features beyond serving Element, I think it'd be a good idea to rename the project.

Most likely to "Matrix Integration" to signify it includes various integrations with Matrix.

cc @Sorunome

[Sorunome]

And the internal app id being matrix_integration then

[gary-kim]

It's almost impossible to change the internal app id. That's actually why Nextcloud Talk, for example, is still using spreed as an app id even though it was renamed years ago. This app also still uses riotchat as the app id.

[Sorunome]

Alright 👍