Remove obsolete code

[TFleury]

Remove code marked obsolete for more than two years.

[Skrypt]

Need to see if we should keep them and remove them only in a major release.

[hishamco]

Agree with @Skrypt to remove them on the next major release

[agriffard]

Still to remove obsolete code.

[Piedone]

Since we already introduce breaking changes in minor versions, which is a no-no with SemVer, why not just do it now. Any objections @Skrypt (since you added the Needs Triage label)?

[Skrypt]

I have no objection as I approved this PR a while ago.

[Piedone]

I'd merge this @TFleury but there are merge conflicts. I'd also fix those but for that, you need to tick this checkbox: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork#enabling-repository-maintainer-permissions-on-existing-pull-requests Could you please do that?

I can also pull the changes and merge them from a PR of my own, but that would remove you as the author.

[TFleury]

@Piedone I don't have the checkbox but I solved the conflicts.

[Piedone]

Great, thank you!