Choose backend to play media in context menu (#1325)

## Description
Adds a context menu option to choose the player backend or transcoding
to start playback. This allows for temporarily swapping to another
backend without having to updating the settings.

### Related issues
A couple comments have suggested this, but I don't think there's a
specific feature request

### Testing
Emulator

## Screenshots
<img width="1280" height="720" alt="play_with Large"
src="https://github.com/user-attachments/assets/2a75756f-5d7f-45f6-8ea6-a406f3d7f3e1"
/>


## AI or LLM usage
None

app/src/main/res/values/strings.xml

@@ -771,6 +771,8 @@
     <string name="show_more">Show %1$s more</string>
     <string name="skip_behavior">Skip behavior</string>
     <string name="skip_behavior_summary">For intros, credits, etc</string>
+    <string name="play_with">Play with</string>
+    <string name="transcoding">Transcoding</string>
     <array name="ass_subtitle_modes">
         <item>@string/ass_subtitle_mode_libass</item>
         <item>@string/ass_subtitle_mode_exoplayer</item>