[Feature Request]: Add touch controls for Windows and Linux based tablets

[ohjhas]

Feature Details

That a tablet mode in desktop versions can enabled (touch buttons) like in android but on Windows and Linux version so Windows/Linux tablet users can play (Add touch buttons on settings) because there is no option like that in 0.6.3 and the latest nightly build.

Feature Purpose

If this feature was on here then tablet pc users could play ST on those devices, and also probably get more users.

Concept Screenshots

Those same buttons on Windows and/or Linux version

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• I have read https://github.com/SuperTux/supertux/blob/master/CONTRIBUTING.md#bug-reports.
• I have verified this isn't a request that's already been submitted as an issue.
• I have verified this isn't a discussion, or an issue with the game, but rather an actual feature request - a currently non-existent, but desired feature.
• In this request, I have only included details about one (1) desired feature.
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[tylerandari13]

I believe this used to be a thing, but was removed for reasons im not aware of. I used a really old nightly and turned on mobile controls on my touchscreen laptop and it worked quite well. Would be nice to bring back.

[Vankata453]

@tylerandari13 #3021 returns those options, that's why I've linked it. I must've forgotten about them when reworking the "Options" menu.