feat(neovim): Rust dev with rustaceanvim & LSP servers installation through OS installer and NOT mason

- Use `rustaceanvim` for Rust development
- `rustaceanvim` keymaps in NeoVim `after` file
- Remove Rust LSP setup through builtin LSP
- Remove LSP installations from Mason when equivalent available through
  OS installers
- All LSP plugins in `code-lsp.lua`

common/.config/nvim/lsp/rust_analyzer.lua

@@ -1 +0,0 @@
-return {}