[API] Add POST and PUT calls in courses API for post_manually

Problem statement:

Manually posting grades is the preferred setting for the Grade Posting Policy at our institution. The courses API allows discovery of the post_manually setting through an include parameter for GET calls, however, the equivalent POST and PUT actions don't allow for changes to be made either at course creation or through an update action. We would like our integration to include this setting when creating new courses through the API. A use case for this is when assignments are set to sections who are taking tutorials on different days of the week and so their assignments are due on different days. Staff would prefer to release grades for the assignment to all students at the same time. New staff are sometimes unaware that grades are available immediately as the default setting.

Proposed solution:

Add an optional include parameter called 'post_manually' that takes a boolean to: https://canvas.instructure.com/doc/api/courses.html#method.courses.show and https://canvas.instructure.com/doc/api/courses.html#method.courses.update In keeping with current settings the default should be 'false' (see note below). Setting include['post_manually'] to 'true' in course creation or update will change the course gradebook setting for the Grade Posting Policy to 'Manually Post Grades'. Note: adding this as an account level setting to determine the default grade posting policy would also be helpful. In this case the default setting when include['post_manually'] is not set should match the account setting. This would allow for bulk updates of courses to align with institutional policies on grade release.

User role(s):

admin