PPA UserInput Selection Screens (EXPOSUREAPP-4752) (#2270)

* PPA User Input Strings

* Data Donation: PPA User Input.
First draft.

TODO:
Districts
Tests

* Fix interaction with radio button..
Fix state matching for NRW
Add district mapping and display.
Fix "unspecified" element position.

* Test skeletons.

* Finish unit tests.

* Wish the LINTer a nice evening.

* Move extension functions into their own file and make them public to allow label-related code to be reused on the settings screen.
Additional unit tests that check the federal state short code mapping.

* XML formatting.

* Address additional PR comments.

* Adjust radiobutton accent color.