Merge branch 'ispconfig-3-3-p2' into 'develop'

Fixes for ISPConfig 3.3 Patch 2

Closes #6869, #6884, #6885, #6889, #6890, and #6881

See merge request ispconfig/ispconfig3!2025

ISPConfig 3.3.0p1

ISPConfig 3.3.0

Fixes #6727 Editing of language files: Invalid language file key

ISPConfig 3.2.12 final release

ISPConfig 3.2.11p2 release

Fixes #6596 improve language file editor input validation

ISPConfig 3.2.11 Release

Merge branch '6544-dashboard-limit-shows-mb-of-unlimited' into 'develop'

Resolve "Dashboard Limit shows MB of Unlimited"

Closes #6544

See merge request ispconfig/ispconfig3!1772