[Plugin] gRPC UI

[savannanoh]

Summary

This plugin would be similar to the current GraphiQL plugin, but it would be for gRPC instead. I am currently working on it for my own usage, but I'd love to share it with the rest of the community as well! (I don't seem to be able to assign myself to this issue, but I would if I could.)

Project website (if applicable)

Here is the documentation for gRPC, which this plugin would be using. I will add other links soon, potentially to the libraries I will use.

Context

Backstage is a really well-made platform with good infrastructure. Since the GraphiQL plugin already exists (and looks great), making the gRPC plugin shouldn't be too difficult.