OpAI annotations and missing platoon templates

[speed2CZ]

Description of the proposed changes

• Annotations for OpAI, description added for the most used functions from the mission scripts

Testing done on the proposed changes

• Sera base in 6th FA mission is correctly building T3 tanks

Checklist

• Changes are annotated, including comments where useful
• Changes are documented in a changelog snippet according to the guidelines.
• Request 2-3 reviewers from the list of reviewers and their areas of knowledge.

[Garanas]

I don't have a method to validate all the changes. But the majority of them look innocent enough. They're just annotations, use of different syntax and/or a few additional templates.