Add "Folder on top" option to sort

[tobiasKaminsky]

• iOS

• desktop (cannot do it)

• Android @tobiasKaminsky

• Server @nextcloud/server-triage

• add option to sorting dialog to "Sort folders on top"

• global option

• check box to indicate that it is enabled

• default: disabled (like now) @marinofaggiana is this also the default on iOS?

• positioning:

  • server: bottom left in option menu
  • Android: at bottom in sorting menu

[jancborchardt]

Closing in favor of nextcloud/android#14669 since we have more info there. :)