[Enhancement]: add new entity "Initiative" and connected relationships with other entities

[jmergy]

Summary

We'll want to have initiative and have it be able to handle baseFields and have it be able to be associated to changemakers, funders, data platforms, and proposals. Open to whatever else makes sense to enable on this for the initial provisioning.

Problem / Opportunity

No response

Proposed solution

No response

Acceptance criteria

No response

Priority

Low