Constellation support for Crew Retrieval helper

[ineffyble]

Right now the Crew Retrieval helper looks at all your polestars, and then shows all the crew who have a 100%-chance combo matching your polestars.

The next logical extension of this would be to look at the constellations in the user's inventory, look at all the potential polestars within each constellation, and find a list of crew who become retrievable if you add that polestar.

We could then let the user view the potential outcomes of opening a given constellation - e.g. have a page, where you select a constellation you own, and it shows you a table of new potential crew (crew retrievable with any of the new potential polestars who were not already retrievable), along with the chance of them becoming available (e.g. if 1 out of 5 polestars in the constellation enables a combo on Sinister Picard, 20% chance. if 2 out of 5 polestars unlock combos for Sinister Picard, 40% chance).

We could potentially aggregate this to assign scores to each constellation too, but that sounds like a later feature.