fix: Rework MAD cleanup handles

[Alystrasz]

Changes

• Mod is not marked as successfully installed when the process failed;
• When mod downloading/extraction fails, mod directory is removed.

Testing

1. Install this PR;
2. Enable MAD (allow_mod_auto_download 1);
3. Try to join Space battle server and cancel mod downloading/extraction;
4. Check your local profile, the remote mod should not appear in the runtime/remote/mods directory.

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Closes #756.

[Alystrasz]

Waiting for #815 to be merged so we have a simple way to cancel MAD process.