Get building on Android

[ndarilek]

Thanks to #345 for getting this started. I took a slightly different approach:

• The NDK prebuilds seem to ship with static zlib, so I hack CMake to find those. I also tweak the dependencies on Android to remove zlib from the build step.
• sqlite3 needs a bit of hackery similar to what was done for Emscripten. I'm actually not sure how/why it doesn't seem to use the vendored compilation artifacts already.

All dependencies seem to compile. Here's where I'm stuck now:

-- Find libraries path: '/home/nolan/android/android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64;/home/nolan/src/duckdb_spatial/build/release/android/deps/local/'                                                                 
CMake Error at /home/nolan/src/duckdb_spatial/CMakeLists.txt:91 (find_package):                                    
  Could not find a configuration file for package "PROJ" that is compatible                                        
  with requested version "".                                                                                       
                                                                                                                   
  The following configuration files were considered but not accepted:                                              
                                                                                                                   
    /home/nolan/src/duckdb_spatial/build/release/android/deps/local/lib/cmake/proj/proj-config.cmake, version: 9.1.1 (sizeof(*void) = 4)                                                                                              

It definitely compiled proj and seems to have found the config but is discarding it for some reason. Going to research that tomorrow.

As an aside, apologies for all the changes in deps/CMakeLists.txt. I'm using VS Code and must have auto-reformatted on one of my saves. This makes a bunch of whitespace changes. I think I fixed the fact that I indent at 2 spaces and the default here seems to be 4, but if these changes are a blocker for this eventually being merged, I could really use help fixing them. I'm a screen reader user, whitespace is essentially silent unless I read character-by-character, and fixing if (...) vs. if(...) is a lot harder and slower when you can't skim and spot the change with your eyeballs. :) Thanks for any help.