feat: add multi speed fast forward (1x-16x) to game menu

[mdevolde]

feat: add multi speed fast forward (1x-16x) to game menu

Motivations

The purpose of this PR is to allow players to have more options when adjusting the game speed (which is currently limited to x1 or x2).

Changes

Interface changes

• Mobile: "Fast-Forward" becomes a list (1x, 2x, 4x, 8x, 16x)
• TV: "Fast-Forward" is now listed in ListPreference with the same speeds as above.

On both platforms, displays the note “Some speeds may be limited depending on the core.”

Code changes

• Added an EXTRA_FRAME_SPEED extra and a RESULT_SET_FRAME_SPEED result.
• The menu returns the selected speed and BaseGameActivity applies it to retroGameView.frameSpeed.
• The "Toggle fast forward" shortcut cycles through 1->2->4->8->16->1.
• Compatibility: fallback retained via the old bool EXTRA_FAST_FORWARD / RESULT_ENABLE_FAST_FORWARD.

Testing

• Tested on mobile: speed selection and menu persistence. On some cores, there is a limit of supported speed (for exemple, x4 and x8 will give the same result).
• Not yet tested on TV (will be performed soon)

Related issues

Closes #650
Closes #837

[mgiessing]

Thanks @mdevolde looks like a nice PR 😊

Two questions:

• Does this PR also enable binding fast-forward to a button/key which is especially useful when using a controller?
• Since I do not have access to a Laptop right now, have you compiled the APK somewhere (or would you and e.g. upload to git?)

[kovasap]

Based on my reading of the description, this does not add a button/key binding. I also really want that feature.

#1077 seems to add this feature though! But so far the PR has been ignored. If you end up building lemuroid with that PR could you share the APK? Or maybe I will try building it myself at some point...

[mdevolde]

@mgiessing @kovasap I didn't add a shortcut for "fast-forward" because it is yet implemented, but I didn't notice that, because this shortcut has no default value, it is impossible to configure it. I will look at this soon.