Remove redundant sdpbuffer.py
Refacory commit. Use Core class for all globallists

These global instances are now under Core class
    UserSessions - authenticated users and their permission data
    Controllers - known controllers
    ServiceGroups - setup data for all service groups
    WsClients - list of active WebSocket connections
    MsgBus - global message bus for webscoket client live updates
    Hosts - all known controller connections