Added SysConfig setting to configure format tags in rich text editor.

[sprengerdaniel]

Proposed change

We want to restrict the available formats in the rich text editor for our agents and customers. So we added a new setting based on Frontend::RichText::Settings###\<setting>

1 - 🚀 feature'

Breaking change

Additional information

• New sysconfig setting's name is Frontend::RichText::Settings###FormatTags.

Checklist

• [X] The code change is tested and works locally.(❗)
• [X] There is no commented out code in this PR.(❕)
• [ ] You improved or added new unit tests.(❕)
• [X] Local ZnunyCodePolicy passed.(❕)
• [ ] Local UnitTests / Selenium passed.(❕)
• [ ] GitHub workflow CI (UnitTests / Selenium) passed.(❗)

[dennykorsukewitz]

Hi @sprengerdaniel, good to hear from you. 😄

Thanks for your PR. From my side this is already approved :+1:

@NiklasSchmitt Please check once briefly and prepare the changes in the CHANGES.md and translations (internally).

Regards :rocket: