Add has permission class decorator

[Maillol]

Decorator that set permission for each aiohttp.web.View method.

@class_has_permission(prefix='booking')
class BookingView(web.View):
     def post(self):
         """
         Require `booking.create` permission
         """

     def get(self):
         """
         Require `booking.read` permission
         """

     def put(self):
         """
         Require `booking.update` permission
         """

     def patch(self):
         """
         Require `booking.update` permission
         """

     def delete(self):
         """
         Require `booking.delete` permission
         """

Note: This pull request is based on #148

[codecov]

Codecov Report

Merging #150 into master will increase coverage by 0.47%.
The diff coverage is 95.74%.

@@            Coverage Diff             @@
##           master     #150      +/-   ##
==========================================
+ Coverage   94.97%   95.44%   +0.47%     
==========================================
  Files          10       11       +1     
  Lines         517      702     +185     
  Branches       18       25       +7     
==========================================
+ Hits          491      670     +179     
- Misses         20       23       +3     
- Partials        6        9       +3

Impacted Files	Coverage Δ
aiohttp_security/__init__.py	100% <100%> (ø)	⬆️
aiohttp_security/api.py	90.62% <81.25%> (+0.38%)	⬆️
tests/test_class_has_permission.py	96.11% <96.11%> (ø)
tests/test_dict_autz.py	96.47% <98.52%> (+0.74%)	⬆️

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[jettify]

Just curious, may be name this function view_has_permission to indicate that decorator works for web.View?

[Maillol]

Yes we can change the name, but if the has_permission decorator is deprecated (#169) I think that we cannot use this API to have set global permission.

[kxepal]

I was thought that not just has_permission was deprecated, but the decorator-way to check permissions is deprecated. Wouldn't this one face the same fate?

[jettify]

should we also check type of cls object and throw TypeError if clsis not web.Veiw?

[jettify]

I have 2 questions, in general I like PR and it has also lot of tests. @kxepal @asvetlov what do you think?

[asvetlov]

If we'll decide to deprecate decorators the PR should be revisited.
Let's postpone merging for now.

[asvetlov]

Thank you for PR.
Unfortunately, I've chosen another solution: no more decorators but check_permission explicit call.