[WIP] Protected branches updates - granular methods (#1443)

* Add get method for required status checks

* Add api urls for required status checks

* change name of apir url for required status checks

* fix xml comment

* add update method for required status checks

* add delete method for required status checks

* fix api url

* fix xml comment

* add api url for required status cehcks contexts

* add get method for required status checks contexts

* add replace method for required status checks contexts

* add add method for required status checks contexts

* add new overload for delete method

* add delete method for required status checks contexts; fix overloads for delete

* add api url for restrictions

* add get method for restrictions

* add delete method for restrictions

* add api url for teams restrictions

* add get method for team restrictions; fix delete method restrictions

* fix overhead for get team restrictions

* fix httpmethod for update required status checks

* add set method for team restrictions

* add add method for team restrictions

* add delete method for team restrictions

* add api url for user restrictions

* add get method for user restrictions

* add set method for user restrictions

* add add method for user restrictions

* add delete method for user restrictions

* Add unit test; fix api urls

* Add ExcludeFromTest class

* add exclude attribute to methods

* Add attribute usage

* Add parameter to interface

* add observable unit tests

* rename excludefromtest

exclude all the tests for the new api endpoints because they broke the
pagination and syncobsverable tests.

* rename excludefromattribute

* refactor observable methods

* [WIP] Add integration tests

* finish integration test

* fix renamed branch protection restrictions

* add team and user collections

* rename set to update

* rename test methods

* optimize integration tests

* made some tidy ups
- fixup comment wording Edit => Replace
- remove spurious characters from description
- remove un-needed exclude attributes

* remove ForOrgRepo tests

* remove unused org contexts

* dispose contexts

* remove obsolete GetRedirect

* add clarifying comment to restriction methods

Octokit/Octokit.csproj

@@ -125,6 +125,7 @@
     <Compile Include="Helpers\ApiErrorExtensions.cs" />
     <Compile Include="Helpers\ApiUrls.Authorizations.cs" />
     <Compile Include="Helpers\ConcurrentCache.cs" />
+    <Compile Include="Helpers\ExcludeFromPaginationConventionTest.cs" />
     <Compile Include="Helpers\HttpClientExtensions.cs" />
     <Compile Include="Helpers\Pagination.cs" />
     <Compile Include="Helpers\PropertyOrField.cs" />