[ServiceDesk] Added the "Create request type" method available on the REST API "requestType" endpoint

[dbarroso]

The requestType API endpoint has a createRequestType method that can be used to create new request types.

Documentation here:
https://docs.atlassian.com/jira-servicedesk/REST/4.13.1/#servicedeskapi/servicedesk/{serviceDeskId}/requesttype-createRequestType

I've added some code to implement this method.

[Spacetown]

Can you use black to format the code or use the black output to update your code?

[gonchik]

Thanks