POC: Make the first three pistol perks (Magnum, Clutch Shot, and Quickdraw) purchasable without TC

[DaloLorn]

(Potentially resolves the eponymous thread, should the proposal be accepted for implementation.)

A proof-of-concept implementation of Suppression Spammer's proposal, allowing most classes to unconditionally spend AP on the Magnum, Quickdraw, and Clutch Shot perks if they appear in a non-class row (presumably, but not necessarily, the pistol row).

Due to a blend of laziness and caution, the configs for this feature can also be reused for any other non-class perks, with the following notes:

• The perk name must be specified in the IGNORE_NO_TRAINING_CENTER array.
• The class name must either be omitted from the CLASSES_IGNORE_CUSTOM_COSTS array, or added to a new CLASSES_ALLOW_NO_TRAINING_CENTER array.
• Again, for emphasis: The perk must be in a non-class row. Class perks are unaffected.

As with my other PR, conformance to LW's code style is questionable at best, but it should work.

[DaloLorn]

Marked as draft, pending tests to be done later today.

[DaloLorn]

Fixed a few syntax errors (hard and soft alike), and successfully completed all tests I could think of:

✅ Can successfully buy the perk without a Training Center (tested fresh out of Gatecrasher!)
✅ Does not override any other requirements (still need the AP to buy the perk!)

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✅ Also applies to other non-class rows, e.g. XCOM row (added NeedleGrenades to my test config)

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✅ Does not apply to class rows (added SlugShot to my test config)

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✅ Does not affect classes specified in CLASSES_IGNORE_CUSTOM_COSTS (added Ghostwalker to my test config)

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✅ Unless they are specified in CLASSES_ALLOW_NO_TRAINING_CENTER! (added Hitman and ShadowOps_FirstAid to my test config)

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Moving out of draft status.