Merge: Remove the packages `glesv1`, `mnit` and `sdl` (1.2), and their clients

This PR removes the packages for OpenGL ES 1.0, most of the graphics engine `mnit` and the SDL 1.2 wrapper `sdl`, as well as their clients: crazy_moles, friendz, memory, mnit_ballz, mnit_dino, shoot and the 2D client of Tinks!.

This purge is mainly motivated by the declining support for OpenGL ES 1.0, it is not available on macOS and on some recent GNU/Linux distributions (including on our test servers). Plus, all the libraries have been replaced by well-supported alternatives: `glesv2` for OpenGL ES 2.0, the graphics engine `gamnit` and `sdl2`. The new libraries are even more portable, adding support for Windows and iOS alongside GNU/Linux and Android.

Some of the deleted games were quite good, it is sad to simply let them go. If anyone is willing to put in the work, most of these games can still be updated to `gamnit` by reverting the commit and writing some code!

@privat  Could you somehow lock the APK files on the F-Droid server so the games live on? They all had Android variants except for `shoot`.

Pull-Request: #2611