Add treesit-admin-generate-compatibility-report

Add treesit-admin-generate-compatibility-report

This function can generate a HTML report on latest compatible
grammar versions for each major mode.

* admin/tree-sitter/compat-template.html: Update.
* admin/tree-sitter/treesit-admin.el:
(treesit-admin--validate-mode-lang): Change so that emacs 30 can
also run it.
(treesit-admin--find-latest-compatible-revision): Support
running checks with a different Emacs executable.
(treesit-admin--generate-compatibility-report): New function.

(cherry picked from commit d9cfe1fe92ffda7e52dcb434e34bfdd1258f2688)