UwUSync Server 0.2.0

UwUSSH Server is UwUSync Server now. It syncs UwURDP as well as UwUSSH, so the old name had
become too narrow. The new names:

• Repository: MinifyX/UwUSync-Server. The old address forwards.
• Image: ghcr.io/minifyx/uwusync-server.
• Command: uwusync-server.
• Settings: UWUSYNC_….
• New installations: /opt/uwusync.
• A new icon.

Nothing changes for the devices: the protocol, the setup codes and the pinned keys stay the same.

• update.sh moves a server from before over by itself, in the directory it is in. It takes a
  backup first. The settings in .env get their new names, the data volume stays the same one,
  and the old container stops only once the new image is on the machine. If the new version does
  not come up, everything from before goes back. CI tests this against a real 0.1.1 installation.
• The old names keep working.
  • The server still reads UWUSSH_… settings, and its log says which ones still have the old
    name.
  • A database called uwussh.db keeps that name, so a rollback still finds it.
  • Backups called uwussh-….db are listed, restored and pruned like new ones.
  • The image answers to uwussh-server as well. It is also published under its old name,
    ghcr.io/minifyx/uwussh-server, for a compose.yaml kept by hand.
• install.sh stops on a machine that already has UwUSSH Server in /opt/uwussh, and says
  how to bring that one over. It no longer sets up a second server next to it.