As a developer, I would like the profile page only makes one API call to get all relevant data

[esparr]

The front end is currently making too many calls to the backend for the profile page. We need to consolidate the profile page information into one endpoint.

Acceptance Criteria:

• the response JSON has 5 fields:
  - [ ] myProfile (JSON)
  - [ ] mentorInfo (JSON)
  - [ ] menteeInfo (JSON)
  - [ ] sessions (list)
  - [ ] notificationSettings (JSON)

• if mentorInfo has data, then menteeInfo is empty (and vice-versa)

• sessions is ordered by start date

• build off of UserProfile viewclass

• change UserProfile serializer_class after checking for self.request.version