Design improvements

We just talked to a UI / UX designer and discussed some new ideas for HedgeDoc 2.0. This issue shall contain a list of to-dos we gathered from the meeting

Common

• https://github.com/hedgedoc/hedgedoc/issues/6835
• https://github.com/hedgedoc/hedgedoc/issues/6836
• https://github.com/hedgedoc/hedgedoc/issues/6837
• https://github.com/hedgedoc/hedgedoc/issues/6838

Explore Pages

• https://github.com/hedgedoc/hedgedoc/issues/6839
• https://github.com/hedgedoc/hedgedoc/issues/6840
• https://github.com/hedgedoc/hedgedoc/issues/6841
• https://github.com/hedgedoc/hedgedoc/issues/6846

Editor

• https://github.com/hedgedoc/hedgedoc/issues/6842
• https://github.com/hedgedoc/hedgedoc/issues/6843
• https://github.com/hedgedoc/hedgedoc/issues/6844
• https://github.com/hedgedoc/hedgedoc/issues/6845
• https://github.com/hedgedoc/hedgedoc/issues/6851