Cleanup and unify templates, possibly add new languages

[jirimoravcik]

Currently, there are some discrepancies between templates, e.g. there's a LangChain template only for JS. Bun template is only for TS. Also scraping and AI agent templates are mixed up. Maybe we should reconsider how we display and offer the templates and also make sure everything is as consistent as possible. E.g. one section for scraping, other for AI agents.

There was also an idea to add other languages than JS, TS, Python to templates, e.g. Go.

[janbuchar]

Also worth noting, the cli-start template is now listed under JavaScript, which is not ideal.

[B4nan]

We should also bump node to 22 and move the dockerfile to the root of the template, and pin the browser dependencies in both package.json and dockerfile (and come up with a way to ensure they are in sync, could be a runtime validation as part of the dockerfile).