Handle replaceable required equipment better

[ibboard]

A required equipment item is "replaceable" if it is both required and has other objects in its mutex group. If this is the case then the implication is that one or more item from that mutex group must be taken.

What currently isn't handled very well is which item is the default selected one. The example data works because the default is the first in the list, but this might not always be the case. We need some kind of "is default" tag to mark the default selection from a group of required items.

[ibboard]

Remove owner so that the team can more easily see bugs. Using default owners seems good at first but is bad practice when a team can be working on any part of the project.

[ibboard]

Move some tickets to v0.2 milestone

[ibboard]

Move tickets to new "confirmed" status to show that they've been checked

[ibboard]

Separate API milestone from UI milestone