Move Scheduling to SNEx2

[moira-andrews]

Move the scheduling functionality to SNEx2 from SNEx1. This includes removing (or refactoring) logic in sync_observations.py and the sync_observations_with_snex1 hook and having various observation types (dynamic, single observation, imaging and spectroscopy) be submitted on SNEx2, appear on the Observations tab and scheduling page as ongoing observation, and appear in the LCO observing portal as a submitted observation. Linked branch has the snex1 hooks commented out, which is a good place to start.

[moira-andrews]

In the cadence strategy scripts, the observation_id is called for an observation, but I'm not sure how this should be defined in the form submitted. Before, it is hard coded as 'template', and snex1 handles the pending observations. If snex2 is submitting, would need to get the observation_id on form submission.

In the cadence scripts: facility.update_observation_status(last_obs.observation_id)

In api_views CustomObservationRecordViewSet, there is observation_ids = facility.submit_observation(observation_form.observation_payload()), but I'm not sure why this code isn't called. In the urls.py the LCO observations from the Observing tab are submitted through CustomObservationCreateView.as_view, which calls the form from custom_code.template_tags custom_code_tags.submit_lco_observations. Maybe the observation create view called here needs a facility.submit_observation to happen? Or maybe the method in api_views needs to be the one called to make new observations.