Add a detail view for redundancy groups

[nilmerg]

With #1050, redundancy groups are listed as part of an object's root problems. They're not clickable yet, though.

Routing

The detail is accessible through icingadb/redundancygroup requiring the parameter id and the hex-formatted id of the group as value.

The View

Click Paths

• Root problem items representing redundancy groups provide a link to this view
• "List all…" links to a new tab

[sukhwinder33445]

The detail view should contain the following details:

• Quick Actions: Same as in Service/Host case.
• Collapsible plugin output: Output of the handled member or member with the worst severity, depending on what influences the redundancy group.
• An RedundancyGroupDetailExtension Hook