Allow to manually disable version manager detection

[DaniruKun]

I personally as an example use nix for everything, but for some projects I still use a version manager like asdf.
A lot of other language extensions allow you to specify a custom path to Elixir, or allow to completely disable the vm detection so it can pick up elixir from e.g. a Nix shell environment.

[Blond11516]

Hi @DaniruKun! I'll transfer this issue to the lexical language server repo since that's where version detection is handled.

[scohen]

@Blond11516, I think that this will require changes on the lexical side as well, since version detection is done in the boot scripts.

[Blond11516]

Yeah that's why I transferred the issue here. There isn't much we can do on the client side to support this (not without changes to the boot scripts at least).

[scohen]

Out of curiosity, @DaniruKun, does this fail if you're using our flake? (I don't know much about nix)