Separate connection logic from TJAlien

• Connections are managed by TJAlienConnectionManager;
  • TJAlien calls TJAlienConnectionManager::CreateConnection() from ctor and TJAlienConnectionManager::ForceRestart() from Token() command when hard reconnect is needed;
• gGrid variables are updated after each command;
  • fUser and fPwd are taken from response metadata, fHost and fPort - by calling TJAlienConnectionManager::GetHostAndPort(TString &fHost, Int_t &fPort);
• Notify the user that TJAlienConnectionManager tries to establish a connection;
• SetSite command;
• TJAlien command parser treats a text in quotes as a single option;