Osu: Hide menu cursor on touch devices

[mcendu]

Describe the new feature: Cursor showing up is not expected and looks bad on touch devices, and should be hidden. Cursor in std mode should not be hidden.

Proposal designs of the feature: When touch input is used, an invisible drawable would be drawn in place of the cursor.

[bdach]

Related to ppy/osu-framework#1514 (probably going to need to expose something framework-side to indicate a touch device is being used).

[ThatsNiceGuy]

Cursor showing up is not expected and looks bad on touch devices, and should be hidden.

I think it looks great and with the cursor rotation it makes the menu cursor feel fun on mobile/touch screens. Also since this is osu!, I feel like not having a menu cursor would be strange considering the type of UI that is being used especially in places like the settings where everything isn’t mobile oriented.
Maybe hiding menu cursor on touch devices could be added as a toggle somewhere near the bottom of the settings or in the section where cursor settings currently are.

[peppy]

a toggle is fine, but the default would be hidden.

[Squiddu]

@ThatsNiceGuy Keep in mind that on mobile the cursor may cause unneeded lag.
(This comment was not needed, just wanted to point it out.)

[mcendu]

Edited description for clarification.