OF-2390: Add warning to admin console for to low ghost detection
When Openfire is configured to remove occupants as MUC ghosts for a value that is shorter than the Stream Management maximum detach time, then detached users run a considerable amount of risk to be misidentified as ghosts. This commit adds a warning to the admin console when such a configuration exists. The warning might not be fully accurate (as there's no telling what maximum detach time remote users have), but can be expected to be 'generally ok'.
OF-2390: Increase default frequency for MUC ghost detection.
The intent of this change is to increase the maximum timeout of IQ Ping requests used in MUC ghost detection. This has been hard-coded to be 25% of the frequency.
A more flexible solution would involve adding a new property that controls the IQ Ping timeout (instead of using the hardcoded 25%), but that'd take some more effort to implement. This change here will have comparable effects, without needing to worry if we'd have to expose a new property on the admin console, etc.
OF-113: Limit lenght of group name/description to database restrictions
The database allows for up to 50 characters for a group name, and up to 255 for a description. The admin panel should not allow the end-user to provide longer values.
