feature: plugin settings read from servers, plugin config files written to every server that loads them

[lukepolo]

Plugin pages get real settings: servers report what each plugin cvar is for and defaults to, and a plugin's config file is managed in the panel and written to every server that loads it.

• game_plugin_cvars, filled over RCON Cvarlist when a server running the plugin comes up; a value only counts as the default where no panel config sets it, and secret-looking cvars never get one
• game_plugin_installs.config is written to the catalog's config_path on every server loading the plugin (a mode's or rotation's file at that path wins), and config_cvar is pointed at it
• Registry sync stores config_cvar, config_default, config_shipped and forced_cvars
• parseCvarList splits columns on :, so a URL value is no longer cut at https
• Migration 1889000001700_plugin_settings plus Hasura metadata for the new table and columns