Unify copy-to-clipboard in Utils

[thgoebel]

This was originally motivated by removing the duplicate Toast on Android 13: https://developer.android.com/develop/ui/views/touch-and-input/copy-paste#duplicate-notifications

Notes:

• For the time being, I have left the two instances of special copy handling in the SettingsActivity.
• The string usage can also be centralised.
  • No need to translate the same string multiple times. Also having "URL copied to clipboard" does really not improve the UX over "Copied to clipboard".
  • Only the the English strings.xml is "clean". The other languages are just "rename the most translated generic one, delete the rest".
  • No idea how to import these changes to Weblate.
  • The 2 special strings for the SettingsActivity are kept.

Tested on Android 12 and Android 13.

[binwiederhier]

Neat, thank you. Sorry for not responding in a long time. I haven't worked on the Android app in a long time. I'll review when I do!