Buff IFA mortars closer to mk6

[jaj22]

What type of PR is this.

1. [ ] Bug
2. [X] Change
3. [ ] Enhancement

What have you changed and why?

IFA mortars were extremely weak so I've buffed them a bit closer to the vanilla ones. Changes:

• Flattened out the wild inaccuracy at higher charge sizes. Still worse than vanilla but not so far off.
• Made effective radius against unarmoured units somewhere near vanilla effective radius against armoured units.

The 60mm mortar was left a bit weaker. Should probably adjust the templates so that enemies all use the larger mortars, because the range and effectiveness of the 60mm isn't really sufficient for use as a support.

Also fixed a couple of config bugs while I was in there:

• IFA config fixes were using the vanilla patch name.
• IFA had a bugged target dummy that broke CBA XEH.

Please specify which Issue this PR Resolves.

closes #3313

Please verify the following and ensure all checks are completed.

1. [X] Have you loaded the mission in LAN host?
2. [ ] Have you loaded the mission on a dedicated server?

Is further testing or are further changes required?

1. [X] No
2. [ ] Yes (Please provide further detail below.)

Should switch the US/UK enemy templates to use 81/82mm mortars, and make the 60mm one cheaper for rebels. Edit: Done

[jaj22]

Ok, some related balance changes:

• Switched the US/UK mortars over to the German 81mm so that they have enough range to be useful.
• Dropped 61K from AK rebel template (too strong against tanks).
• Decreased price of 60mm mortar because it's pretty bad.