Stravalib2.0 -> Maintain Strava's meta-summary-detailed type hierarchy

[jsamoocha]

This should prevent response objects with many None fields and make it more explicit to users what level of detail they'll get from an API call.

• Update client methods to ensure the correct detail level is returned
• Check the model for instances where we override stuff from other than detailed-level objects

Depends on #498

Update: As a reminder: this will also close #198

[lwasser]

it will be a lot less confusing to have fewer of these empty response objects. Will this also then address the comment in our discussion surrounding laps? i still haven't had a chance to look into that but i have noticed empty returns.

[jsamoocha]

Yes, exactly. We discussed this some time ago, and this recent issue triggered me to fix this now that we remove that BackwardCompatibilityMixin and introduce breaking changes anyway.

[lwasser]

perfect! i tested this and it's working well lately via your latest pr!! so much better!

[lwasser]

Client methods that return iterators

• get_activities (Adds Strava type hierarchy for Activity type #505)

• get_athlete_koms

• get_segment (Summary segments #509)

• get_Starred_segment (Summary segments #509)

• get_club_activities()

• get_club_members

• get_club_admins

• get_activity_comments ()

• get_activity_kudos

• get_activity_photos

• get_activity_laps ()

• get_related_Activities (REMOVE Fix: remove deprecated client methods #514 )

• get_friend_Activities (REMOVE Fix: remove deprecated client methods #514 )

• get_starred_segments

• get_athlete_starred_segments

• get_segment_efforts

• get_routes ()

---

• get_athlete ?