Add support for JetBrains IDEs

[BackThePortal]

JetBrains IDEs provide support for LSPs. Looks like adding support for them would be pretty straight forward: https://plugins.jetbrains.com/docs/intellij/language-server-protocol.html#basic-implementation

I would try to do it myself, but I don't have experience with Kotlin, Rust nor plugin development. But I can try to help to add features to the plugin when it's done.

[angelozerr]

@BackThePortal the LSP support from Jetbrains is only available for Ultimate, but if you want to provide a free IJ plugin, please try https://github.com/redhat-developer/lsp4ij

If you want to evaluate LSP4IJ without developping an IJ plugin, you can do that just by setting the start command of your LS and the mapping between your LS and files, see https://github.com/redhat-developer/lsp4ij/blob/main/docs/UserDefinedLanguageServer.md

After that if you think LSP4IJ is good for you can could create an IJ plugin (see https://github.com/redhat-developer/lsp4ij/blob/main/docs/DeveloperGuide.md)

It is better to write an IJ plugin to define custom LSP client command, download your language server, etc