feature: send the workshop addons of the plugins a server loads

[lukepolo]

Servers now get the workshop addons of the plugins they load, from the registry's new workshop_addons field, as WORKSHOP_ADDONS for game-server to hand to AddonsManager.

• game_plugins.workshop_addons column (migration + permissions), synced from the registry
• Worked out from the final plugin list, next to the server guidelines check: mode, auto-load, community server switches and map rotation all count
• From the catalog, not the installs, so a hand-placed plugin a mode loads still gets its addons
• Each id once, in load order; anything that is not a bare number is dropped

Needs codegen after the migration and metadata are applied.

Together with 5stackgg/plugin-registry#6, #498, 5stackgg/game-server#211 and 5stackgg/web#680.