hls-stan-plugin shouldn't be included by default

There are several reasons to distribute HLS sources without Stan included by default:
1. Stan still marked as beta after a 4 years of development.
2. Stan has a large dependency footprint.
3. The Stan plugin is disabled by default in text editor plugins.
4. If you want to disable it as a dependency, you must rebuild and redistribute HLS.

As an HLS user, I encountered problems while trying to modify the HLS binary distribution with Nix due to the lack of support for Stan dependencies (extension library). I’ve been having conversations with several active Haskell open-source contributors who also disable Stan entirely.

What is the history behind enabling Stan by default? Is it necessary to invest time into adopting a tool with limited support?

Mark this issue with 👍 if you think (or 👎 if not) the `hls-stan-plugin` should not be enabled by default. Share any stories about why you disable stan