docs: use information from the previous release to create pages

[ldez]

use 2 references files:

• one for the reference of the released version (.golangci.reference.yml)
• one for the next release (.golangci.next.reference.yml)

I restored .golangci.reference.yml from v1.56.2 tag.

.golangci.next.reference.yml contains the new elements related to the next release.

I also added a workflow to update automatically .golangci.reference.yml with .golangci.next.reference.yml after a release.
The update will be done automatically in the same generated PR that updates the GitHub Action assets.

---

The target expand_website_templates has been renamed to website_expand_templates.
Previously, the target expand_website_templates was using calls to the Manager and output from help commands.
Now the target website_expand_templates uses the files generated from another target website_dump_info.

website_dump_info uses calls to the Manager and output from help commands to create JSON files.

The update will be done automatically in the same generated PR that updates the GitHub Action assets.

---

The file .golangci.reference.yml is used to generate the documentation (configuration and linters pages).
Then the documentation about new options will not be published before a release.

If we need to fix something in the current doc, we should update the file .golangci.reference.yml.
If we need to add new options or linters, we should update the file .golangci.next.reference.yml.

If there are fixes to linters information, the generated file assets/linters-info.json should also be updated by hand.

Related to #4450
Related to #4255

[bombsimon]

I hope I didn't miss anything but this seems to simply be a split of the old code in a single main.go file to several files and the big diff (additions) is due to the copy of the reference and the new JSON files?

If so, feel free to ignore my comments about any code, this LGTM. Nice with a file that targets the latest release separately!

[ldez]

the big diff (additions) is due to the copy of the reference and the new JSON files?

yes exactly

[Antonboom]

a lot of code 💥
thank you for your job!