[feat] gitea: implement dedicated module

[Bnyro]

What does this PR do?

• implement a module for gitea
• by default we only have a codeberg engine available (as before)

Why is this change important?

• it provides more details than before
• see Use the template packages.html #3268

How to test this PR locally?

• !cb foot
• !cb gadgetbridge

Related issues

see #3268

[return42]

implement a module for gitea

yeah having a gitea module is much better: developer can now search their local gitea instance .. in best quality .. 🚀

To make it more clear in the commit history, we should split the commit into two; in the first add the python module and in the second move codeberg from XPath engine to gitea engine.

Can you please split the commit? .. afterwards I can squash some more documentation into the gitea module / thanks a lot!

[return42]

FYI: I added the engine to the online docs / when merged into master available at: https://docs.searxng.org/dev/engines/online/gitea.html

[Bnyro]

FYI: I added the engine to the online docs / when merged into master available at: https://docs.searxng.org/dev/engines/online/gitea.html

Thanks, looks good to me 👍