Built-in Protobuf Support

[haruki-nikaidou]

Currently, Zed supports Protocol Buffers via an extension that relies on lasorda/protobuf-language-server as an external LSP. However, this project seems like almost unmaintained since July 2024.

And it doesn't work well:

• Protobuf support doesn't work out-of-the-box…? #21057 and How to configure the proto extension? #22308 shows an external LSP cause some confusing because of the configuration requirement.
• Incorrect syntax highlighting in Proto extension #22564 shows that there do be some bugs in that LSP (or tree-sitter) and nobody is working on it.
• Add buf's LSP as option for Proto language #28256 shows that use buf instead of that LSP is a better choice.

Given that Protobuf is a widely-used serialize/deserialize format in many codebases, especially in microservices and API development, having built-in support like rust or go would greatly improve the develop experience. Rewriting that LSP in rust and integrating it directly into zed's codebase would also make it easier to maintain.