Adjustable number of last visited repos

[zc-devs]

Clear and concise description of the problem

Now, last visited repos header have 4 items.

1. It might confuse, in which directions it is sorted in desktop view.
   Screenshot 2024-11-21 131025
2. it might fill too much space on the screen.
   Screenshot 2024-11-21 175000
   ^ almost a half of 4K
3. One might want to disable this header completely.

Suggested solution

Make the number adjustable. 0 - disabled.

Alternative

Make the number of last visited repos = 2.

Additional context

WP next-350082cd19, Gitea 1.22.3, Postgres 16, Kubernetes v1.30.6+k3s1
#4386 (comment)

Validations

• Checked that the feature isn't part of the next version already [https://woodpecker-ci.org/faq#which-version-of-woodpecker-should-i-use]
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[anbraten]

There was also another idea to pin repos instead.

[zc-devs]

pin repos

I personally thought about it also, but it is completely different implementation and idea, I wanted to be on the same page with original PR.
Pinning the repos approach solves this FR, #4426, #4517 and partially #4428.