Use same names for configuration sources in UI and docs
Summary:
Confuse admins less by using the same names in the UI and in the docs.
Closes T16279
Test Plan:
* Go to a random config setting, e.g. http://phorge.localhost/config/edit/translation.override/, and under "Current Configuration", look at the names in the "Source" column
* Go to https://we.phorge.it/book/phorge/article/advanced_configuration/#configuration-sources and look at the names of the options
Reviewers: O1 Blessed Committers, mainframe98
Reviewed By: O1 Blessed Committers, mainframe98
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Maniphest Tasks: T16279
Differential Revision: https://we.phorge.it/D26400