* remove builtin cm list
* add bootstrap_from_dns to resolve cm0.steampowered.com
* add error and logging when cm server list is empty
* add auto_discovery flag; true by default
* when CMServerList is empty it will try to bootstrap from webapi, with dns fallback
* rework SteamClient CM server persistance logic
* move discovery logic from CMServerList to CMClient
* propagate connect() return through all login methods
* detect stale persisted cm list and update
Rossen Georgiev
Rossen Georgiev