[API Docs]: Teacher API Docs

[Jesulayomy]

Fixing teacher API Docs. Currently PUT, POST requests do not work in /apidocs route.

This will be fixed by:

• Splitting yml files for each request type.
• Writing yml for each method in its own file.
• Attaching files to methods using the @swag_from decorator of flasgger.

[Jesulayomy]

@pardeep-singh Will use this issus for Teachers route