Added Inverse Angle Units

[mcgougwm]

Added Inverse Angle Units

[angularsen]

What are some typical use cases for this quantity?

Just trying to make sure the quantities are widely used and avoid bloat, we have a small issue with binary size. I could not find much references by a quick google.

[mcgougwm]

Probably not very widely used, but a lot of our stability and control derivatives are in inverse degrees or inverse radians.

[angularsen]

Since we have 100+ quantities and 1000+ units, I am hesitant to start adding the inverse variant of all our quantities and units.

We are adding #954 , but that one does seem like a widely used quantity with both wiki article and online converters for.

Are you OK with closing this PR, or do you still see value for others in adding inverse angle?

[angularsen]

@mcgougwm I see you deleted the branch so maybe this is a bit late, but I've learned in #954 and #955 that reciprocal angle is also commonly used. So if you are still interested in adding it, I'm happy to merge it.