Feature/dim ambassador events

[allison-code-dot-org]

Description

This PR builds one main model for release: dim_ambassador_events that combines platform activity of students associated with ambassadors' sections and survey responses from the event impact survey. There is one row per event-- although, in the case of an ambassador who has multiple sections of students and holds multiple events in a single school year, these are aggregated into a single row (a rare case).

• meant to answer questions like: what is the impact on enrollment intent of ambassador events? how many students on average attend ambassador events? what is the split between experience CS and connect with CS events? Is one more effective than the other?

Other important notes:

• impact_eval_flag is an important filter the end user will need to know to apply when evaluating program impact, since they would only be able to use event impact survey responses who had before and after numbers for intent to enroll. The programs team is well aware of this, and did not want these rows filtered out beforehand.
• the release of this model would imply the deprecation of dim_ambassador_activity since that information becomes redundant. There are some queries that depend on that model that need to be switched over to reading from dim_ambassador_events before it can be fully deprecated.

Links

Jira ticket(s): DATAOPS-1133
Data Product Brainstorming Doc (not a formal spec)