Add UI to enable manual linking of Incidents

[lunkwill42]

The Argus data model supports the notion of registering relations between alerts. The nature of a relation is entirely up to the user, which can add new relation types.

We need to discuss how to build a UI to enable manually adding relations between alerts.

Examples could be:

• Selecting a set of individual Incidents, and relate them all to each other, to describe, e.g., that these Incidents really are the same thing from different subsystems
• Saying one Incident is caused by another.
• Grouping Incidents to say that they have the same root cause.

[jorgenbele]

What is the current situation regarding this feature? @lunkwill42 @hmpf With #232 I've now added support for selection of multiple incidents, and doing actions on them.

Implementing of "grouping incidents" seems to be viable, and shouldn't require many changes.

[hmpf]

Blocked by Uninett/Argus#313.

[hmpf]

Grouping incidents may be easy, but giving that group a type, and treating it differently depending on type, is tricky. In a "caused by"-relation, the causer and causee needs to be treated differently, but in an untyped grouping, they need not be. If the group is used to hide incidents (duplicates, say), there needs to be a decision on what to show instead: one of the incidents (which one?) or a meta-incident (looking like what?) See Uninett/Argus#313.