Add global setting to not filter default Incident list by owner

[baryluk]

We are small company, and for visibility it is usually best to show all incidents when showing incidents, instead of only ones targets at logged individual.

Also we often use shared slack channels. So the incident goes to a slack channel, not a person, so the target does not match the person that owns it either.

I think it might be beneficial to show all active unresolved accident, without any target or owner filter by default.

Of course configurable, as for bigger deployments it would not work well.

WTYT?

On a related note, it would be cool to see not just my incidents, but also my teams incidents. Not sure how would one handle such thing in iris tho.