v4.23.0: Fix CMS Nav Link (v0 Styles), Manage Group Permissions

What's Changed

• chore: delete unused [templates] by @wesleyboar in #906, #907
• fix: CMS nav link alignment (retrofit to Core-Styles v0) by @wesleyboar in #909
• fix: typo in our djangocms-picture css selector by @wesleyboar in #910
• feat: better group perms mgmt by @wesleyboar in #895

Full Changelog: v4.22.0...v4.23.0