Rollup merge of #7298 - flip1995:ci-switch-to-monster, r=xFrednet,flip1995

Switch CI to new metadata collection

r? `@xFrednet`

Things we have to keep in mind:

- This removes the template files and the scripts used for deployment from the checkout. This was added in #5517. I don't think we ever needed those there. Not sure though.
- ~~As a result, we can't remove the python scripts yet. We have to wait until this hits a stable Clippy release.~~ I'll just break the next stable deploy and do it by hand once.
- This should be merged together with #7279. Me and `@xFrednet` will coordinate the switch
- ...?

I still have to try out some things:

- [x] Is it worth caching? Yes
- [x] ~~Is it worth to do a release build?~~ Nope
- [x] Does it actually work? With a few changes, yes
- [ ] ...?

changelog: Clippy now uses a lint to generate its documentation 🎉

clippy_lints/src/utils/internal_lints/metadata_collector.rs

@@ -32,7 +32,7 @@ use clippy_utils::{
 };
 
 /// This is the output file of the lint collector.
-const OUTPUT_FILE: &str = "../util/gh-pages/metadata_collection.json";
+const OUTPUT_FILE: &str = "../util/gh-pages/lints.json";
 /// These lints are excluded from the export.
 const BLACK_LISTED_LINTS: [&str; 3] = ["lint_author", "deep_code_inspection", "internal_metadata_collector"];
 /// These groups will be ignored by the lint group matcher. This is useful for collections like