feature: restrict community servers to picked players, a role or a live event

[lukepolo]

Lets an admin restrict who may connect to a community server: hand-picked players, everyone at or above a role, or members of an event while it is live. Moderators and up always get in.

• servers.access_restricted / access_min_role, server_access_players, server_access_events; resolved by server_allowed_steam_ids() in hasura/functions/servers/server_access.sql
• Player Management sync returns an access block (restricted, version, denied); new GET /sanctions/server/:id/access returns the full list for the plugin's connect gate
• Connect info is hidden from anyone not allowed, which also drops the server from Public Servers for them
• setServerAccess admin action saves the rules and sends player_management_refresh; no restart
• Includes setServerSettings (feature: save a community server's settings in one call with one restart #473): one save for rotation, plugins and access, restarting the server at most once