Update servers_v7.json: factory server

[prof-milki]

New server instance, Europe, static IPv6-only (works surprisingly well), single game mode (for now). Intended as fallback server due to other networks having recurring downtimes, and are somewhat dilatory with new maps.

[ ] Does not currently fulfill all requirements of SERVERLIST.md - specifically no #2 automated NSFW blocking (gonna test the content verification plugin, if the need arises / unlikely to be an issue initially). [x] Moderation/discourse is still in the works.

If your pull request is not translation or serverlist-related, read the list of requirements below and check each box:

• [ ] I have read the contribution guidelines.
• [ ] I have ensured that my code compiles, if applicable.
• [ ] I have ensured that any new features in this PR function correctly in-game, if applicable.