Modernize Android support

[alexfmpe]

#846 will switch reflex-platform to a modern nixpkgs with a working GHC 9.12 including JS backend.

For Android builds with GHC 9.12 we also need at least

• Non-TH builds
  • haskellPackages: fixes for pkgsCross.aarch64-android-prebuilt NixOS/nixpkgs#355543
  • haskellPackages: fix GHC 9.12 on android  NixOS/nixpkgs#414317
• TH builds (replaces the splices method)
  • haskellPackages: support template-haskell and test suites when cross compiling NixOS/nixpkgs#445672

While reflex-platform was dormant, new requirements also popped up for apps on Google Play

• SDK 35+
  • Bump android target sdk version to 35 #852
• 16kb page size
  • NDK 28+
    • android-ndks: add 27 & 28 NixOS/nixpkgs#415463
  • Android Gradle Plugin 8.5+
    • Support Android Gradle Plugin 8.13 #849

I don't know what the support for 32-bit Android is like upstream on ghc/nixpkgs, and probably not worth even looking into it until 64-bit is working again.

[alexfmpe]

I've stepped down as reflex-frp maintainer out of frustration with lack of engagement from the admins.
As such, I don't plan to spend more of my free time on this - with the exception of the nixpkgs PR, the above efforts are to the best of my knowledge abandoned and in need of someone to pick them up.

[augyg]

16kb page size should be fixed by #853