Feature: Display Omega icons for hulls and modules

[Skybladev2]

Problem

Some hulls and modules can be used by Omega clones only, but it's not reflected in Pyfa item list.

This makes building Alpha-clone friendly fits difficult, as there is no clear indication if a module will work.

Solution

Display Omega icons for hulls and modules both in item list and fits:

Implementation details

The Omega modules/hulls are gated by skills only (proof: esi/esi-issues#133 (comment))
The Omega attribute is calculated and persisted for better performance.

[DarkFenX]

I think ideally this thing should be done via some kind of a filter (done with an "alpha mode" which can be toggled somewhere). But, i'd keep it for pyfa-NG or w/e it's gonna be called.

This one I think is nice to have, but as an opt-in feature. Can you make it disabled by default, and make it so that it can be enabled via options?

The reason for that is that pyfa is definitely a power user tool in my opinion. People who get to using it usually have access to omega, and unnecessary (for them) visual clutter is not something nice-to-have.

[Skybladev2]

make it disabled by default, and make it so that it can be enabled via options

Done.

I would argue that Pyfa is more for powerful users. I think it's more valuable for newbros, but their use cases much simpler.

The original reason I introduced the feature was the situation when I fitted my ship with Omega modules at the end of the subscription.
Then I logged off in space, logged in next day and found out my Omega modules were unusable.
I would make the fit Alpha-friendly beforehand if it was indicated in Pyfa.