Adjust design of documentation

[mariobehling]

Please use the same theme with the eventyay colors and logo as eventyay-tickets.

Then adjust the design of the documentation as follows:

• Change the name "venueless" to "eventyay" everywhere
• Welcome to "Welcome to the documentation of the eventyay tickets component!"
• Use eventyay logo and color as in Django
• Change "Copyright Notice" to "© 2025 Apache 2.0 License by contributors" and reduce font size of Copyright notice
• Change blog to https://blog.eventyay.com
• Add eventyay favicon
• Github https://github.com/fossasia/eventyay-video/
• Twitter to X and link to https://twitter.com/eventyay
• Change let us know link https://github.com/fossasia/eventyay-video/issues/new
• Find other instances where links and mentioning to venuelss or other channels should be updated, e.g. also plugins and fix them.

[r3yc0n1c]

working on it