Need to register language ids for non-bundled languages

[phillco]

For languages that aren't bundled inside of VS Code (like Kotlin, Jupyter, Talon), the language plugin needs to be installed for the languageId to be valid. (We don't need any other functionality of the language plugins, just the valid languageId).

Two options:

• Make these dependencies of the sidecar
• Just make the sidecar register these languages and don't install the plugins

It depends how we implement #7, since if we do that we want to have an isolated sidecar environment with as few custom plugins as possible.