Android: Android INI section and make platform tab selection an INI setting

[Ebola16]

Implements https://bugs.dolphin-emu.org/issues/10793
Prerequisite for https://bugs.dolphin-emu.org/issues/10957

Android-specific settings should be moved away from SharedPreferences and use INI settings. This allows these settings to be retained across multiple builds of Dolphin. I added an Android section to Dolphin.ini to make these settings easy to find. Most of the setting changes will happen in future PRs.

Android: Make last platform tab selection an INI setting was a test case. Now Dolphin will remember which platform tab was selected when (re)installing or starting Dolphin.

[JosJuice]

Adding a new INI section and putting the current tab selection in it makes sense, but why are you moving those two existing settings to the new INI section? For the savestates enabled setting, it is true that that setting currently only exists on Android, so it is debatable, but moving it resets the setting and it might make sense to make that setting available on non-Android in the future. For the DSP setting, I don't see how it would work correctly after the move.

[Ebola16]

I can see the reasoning to leave the savestate setting alone.
I moved the DSP setting since the "master" setting is Android-specific. The logic based on how that "master" setting changes the universal DSP settings still works from my testing. Is this a bad idea?

[JosJuice]

I moved the DSP setting since the "master" setting is Android-specific. The logic based on how that "master" setting changes the universal DSP settings still works from my testing. Is this a bad idea?

Oh, sorry, I thought it was a normal DSP setting and not a special Android one. I suppose it makes sense then (though maybe this setting actually shouldn't exist, if possible... But that's out of scope for this PR.)

[Ebola16]

Reverted the savestate change and kept the DSP Android-specific changes. I didn't want to make changes to the way Dolphin handles DSP settings in a PR that made Android UI changes so that's for a future PR. Unifying the settings will likely involve some INI clutter regardless of this PR.