This also does improve the over-purchase problems, though I can't spot
the behavior change that's causing that. Presumably the old
implementation had a bug I can't spot and in rewriting it I solved the
problem...
Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1582
Since the theater commander runs once per campaign action, missions that
do not have aircraft available may be checked more than once a turn.
Without deduping requests this can lead to cases where the AI buys
dozens of tankers on turn 0.
Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1470
After completing the new game wizard but before initializing turn 0,
open a dialog to allow the player to customize their air wing. With this
they can remove squadrons from the game, rename them, add players, or
change allowed mission types. *Adding* squadrons is not currently
supported, nor is changing the squadron's livery (the data in pydcs is
an arbitrary class hierarchy that can't be safely indexed by country).
This only applies to the blue air wing for now.
Future improvements:
* Add squadron button.
* Collapse disable squadrons to declutter?
* Tabs on the side like the settings dialog to group by aircraft type.
* Top tab bar to switch between red and blue air wings.
This makes it so that the mission planning effects are applied only if
the package can be fulfilled. For example, breakthrough will be used
only if all the BAI missions were fulfilled, not if they will *attempt*
to be fulfilled.
