feat: Re-introduce page-level publish permission just as in v4.0

[fsbraun]

Description

In django CMS version 4.1 the can_publish permission was removed. With the next release of djangocms-versioning it will support low-level publication permissions if the versioned content model supports it.

This PR restores the can_publish permissions and its test as it was available in django CMS 4.0.

Tests have been restored, too.

A (no-op) squashed migration was added to ensure that publish permissions are not lost during migration processes:

• 0035 removes page publish permissions (released in 4.1.0)
• 0036 adds the page publish permissions back
• Squashed migration 0035 replaces 0035 and 0036 with a no-op

Related resources

• feat: Add content object level publish permissions djangocms-versioning#390
• fix: Remove can_publish permission from django CMS 4 core #7635

Checklist

• I have opened this pull request against develop-4
• I have added or modified the tests when changing logic
• I have followed the conventional commits guidelines to add meaningful information into the changelog
• I have read the contribution guidelines and I have joined #workgroup-pr-review on Slack to find a “pr review buddy” who is going to review my pull request.

[vinitkumar]

@fsbraun I was wondering if it's possible to have test covering this change, just so that if there are regressions in this part of code, we can catch it.

[fsbraun]

@vinitkumar The publish permissions are tested. When they were removed, they were removed with their tests... Now, this PR brings both permissions and tests back.