OF-2519: Fix MUC room membership with groups
When loading an individual room (eg: at boot time, when room preloading is disabled), ensure that a MUC room member JID is evaluated as a group JID.
OF-2518: Attempt to load favicon over HTTPS
This adds an additional attempt to load the favicon. With this, both HTTPS and HTTP are attempted.
Additionally, the URL that's used is now being constructed through a builder, which should further reduce the attack vector of using 'user-provided input'.
