feat: Weapon rebalance

[EttyKitty]

As per original description by @KRdaMystic:

Intent:

• Create a definite Hierarchy for weapons including tiers and classes to ensure player has meaningful armament choice and progression in the Armamentarium for his marine's equipment.

• Rebalance damage and max kill values in line with the established hierarchy and class system.

• Balance durability for all ground units so that chapters can tackle targets as less than a doom stack.

• Create descriptive guide documentation for each weapon class so as to guide future additions. (Half way done)

Desired End-state

• Weapons are tangible choices with trade-offs that affect battle outcomes.

• Squad loadouts are more indicative of intended battlefield role (Tank hunters and Horde breakers).

Noticeable changes

• Heavy Bolter is no longer AP.
• Missile Launcher is now AP.

Notes

A related PR: Adeptus-Dominus#315
A structured doc with all said rebalance changes:
https://docs.google.com/spreadsheets/d/1ZMPRXjmd3tWvFmWiIYb-nQ9qT5PYPiu_75SJNhcYqvg/edit?gid=1993273333#gid=1993273333

[EttyKitty]

A couple of general notes about the PR:

• Re combi secondary weapons, as per one of the comments: I think it would've been more streamlined to just give them the same stats as a full-sized gun with less ammo, as per most of the references that have stat mentions.

• Re tags: is it necessary to add all of these new tags? As it stands right now, we're just repeating the same mistake that already existed - adding more words into the tag tooltip line, that do nothing at the moment.

• Re Integrated Bolter: does it make sense to remove the Underslung Bolter and replace it with the Integrated Bolter in all instances, for consistency?

• Re "integrated" prefix: as I was thinking that Integrated Bolter needs to be renamed into "Integrated-Bolter", for consistency, I thought - does it make sense to call them integrated? I.e. a dreadnought or a vehicle may have a bolter or other weapon integrated into the hull/armour. The game adds the "Integrated" prefix to all second profiles that don't have it, i.e. "Bolter" will turn into "Integrated Bolter" if used as a second profile, hence creating a confusion.
  Maybe change "Integrated" on combi variants to something else?

• Re some of the weapon buffs: I saw, namely, that Missile launcher is now AP, has buffed damage and 3 times more spli. My only concern, in this case and other similar cases, is how it compares to its current price that is still unchanged?

[EttyKitty]

Migrated to Adeptus-Dominus#352.