Add user blocking (#29028)
Fixes #17453
This PR adds the abbility to block a user from a personal account or
organization to restrict how the blocked user can interact with the
blocker. The docs explain what's the consequence of blocking a user.
Screenshots:
![grafik](https://github.com/go-gitea/gitea/assets/1666336/4ed884f3-e06a-4862-afd3-3b8aa2488dc6)
![grafik](https://github.com/go-gitea/gitea/assets/1666336/ae6d4981-f252-4f50-a429-04f0f9f1cdf1)
![grafik](https://github.com/go-gitea/gitea/assets/1666336/ca153599-5b0f-4b4a-90fe-18bdfd6f0b6b)
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Co-authored-by: Lauris BH <lauris@nix.lv>