Record which GHC bindist a HLS bindist is built with/against

Related:

* https://github.com/haskell/haskell-language-server/issues/2900
* https://github.com/haskell/vscode-haskell#ghc-abis-dont-match

It might be somewhat annoying for end-users to figure out how to override the stack installer precisely. They would need to know which GHC bindist `ghcup` would install on their platform (but they might not be using it), because ghcup is used when building HLS in CI: https://github.com/haskell/haskell-language-server/blob/9e1738e8c59e2ee5a4a0c17fca2154b936bb7a49/.gitlab/ci.sh#L27

Also relevant: https://gitlab.haskell.org/ghc/ghc/-/issues/21590