Make neovide GL implementation configurable

[coderabbitai]

Background

Currently in PR #1184, the neovide wrapper for GL support is hardcoded to use nixGLIntel:

neovide =
  if cfg.needsGL
  then
    pkgs.writeShellScriptBin nvim.packages.x86_64-linux.neovide.meta.mainProgram ''
      ${lib.getExe nix-gl.packages.x86_64-linux.nixGLIntel} ${lib.getExe nvim.packages.x86_64-linux.neovide}
    ''
  else nvim.packages.x86_64-linux.neovide;

Issue

This implementation only works for Intel graphics cards and might cause issues on systems with NVIDIA or AMD graphics.

Suggested Solution

Make the GL implementation configurable, either by:

1. Auto-detecting the GPU vendor using config.hardware attributes
2. Adding a new option like profiles.base.glPackage to allow explicit configuration

Example implementation:

neovide =
  if cfg.needsGL
  then
    let
      glPackage = if config.hardware ? nvidia && config.hardware.nvidia.enable
                  then nix-gl.packages.x86_64-linux.nixGLNvidia
                  else nix-gl.packages.x86_64-linux.nixGLIntel;
    in
      pkgs.writeShellScriptBin nvim.packages.x86_64-linux.neovide.meta.mainProgram ''
        ${lib.getExe glPackage} ${lib.getExe nvim.packages.x86_64-linux.neovide}
      ''
  else nvim.packages.x86_64-linux.neovide;

This issue was requested by @NobbZ in PR #1184 comment.