Compact all missile ammo entries when using it by type

[rogueranger1993]

I generally prefer to use missile ammo by type rather than launcher size, but switching that option on doesn't change any of the ammo entries in the Warehouse, Parts in Use, and Purchase Parts menus. This results in all of the individual missile ammo types getting repeated for each launcher size and thereby clogging up the menus. As a fix, I'd like to see all entries for missile ammo in the above mentioned menus compacted to a single 'LRM Ammo' entry for each munition type when the option to use missile ammo by type is turned on.

[sixlettervariables]

This is very complicated under the hood and would require MegaMek understanding an AmmoType that could have variable rack sizes. I do not think we'll be able to do this gracefully.

That being said, I'm leaving this open because perhaps before the Amaris Civil War we could get something like this implemented.