Add functionality for tierLicenseCapacity on sites

[jorwoods]

This adds support to the SiteItems to allow it to be used to manage the license level specific counts.

[t8y8]

🚀

[shinchris]

#777 covers tierLicenseCapacity support, though it doesn't include the property_is_int annotation and user-quota limitation. Do you mind waiting until that one is checked in?

Also I think the integer annotation on these are a bit tricky - I'm not sure if there is a limit to the value and -1 is a valid value to indicate reset

[jorwoods]

This can wait until #777 is in. I don't like having the hardcoded upper bound in there either. I can replace it with a sys.maxsize and replace the lower limit with -1.

[shinchris]

That works! I would keep the lower limit at 0 and pass in -1 as the allowed parameter, to keep it consistent with how it's done in request_options.py.

[jorwoods]

@shinchris Question regarding the -1 to indicate reset: I had tested on my own server by passing None to the tiered capacities when I wanted to remove them. Should it be -1 instead? It seems that unittest doesn't like trying to evaluate a range with sys.maxsize as a bound (even though via ipython it has the same run time as any other range evaluation). I had to add a range to property_is_int to be able to add None to the allowed kwarg.

If you think it should be able to accept None, I can either:

1. Modify property_is_int to evaluate in a different order to be able to remove the range restriction,
2. Add a nullable_int type checker
3. Remove None as an acceptable value, and change the check against user quota

[shinchris]

@jorwoods I think it should be -1 instead. Passing in None does remove the tier capacity limits, but it must be all 3 tiers at the same time. For example, if you just wanted to set tierViewerCapacity back to its default, you need to pass in -1 for that one value. Setting just the 1 tier to None (omitted from api request) will not be accepted by server.

For the property_is_int decorator, perhaps we can make it handle a no-max range. If the max value in the tuple is None or some specific value, we don't check the upper bound.

[jacalata]

Why is this variable named "reset"? It could have always been empty, right?