AIDL Language Server Protocol (LSP) server

Features:

• diagnostics
• workspace symbols (Ctrl+T in vscode)
• document symbols (Ctrl+Shift+O in vscode)
• goto definition (Ctrl+Click in vscode)
• hover (mouse over in vscode)
• vscode extension

TODO:

• handle watched files
• type definition
• semantic syntax highlighting

For language-specific features, see rust-aidl-parser.