[BE] Framework source stored on creation of framework

Parent Epic

&15864

Background

We're introducing the ability to designate a group as the Compliance and Security Policy (CSP) group. Frameworks and policies created in this group can be enforced across all top-level groups in the instance.

During the processing of the propagation we want to identify the origin a framework is being applied from, so we're looking to record the source for this purpose.

Implementation

Populate the source column to on creation of a new framework during the creation process in ee/app/models/compliance_management/framework.rb.

Backfill existing frameworks' source.

Acceptance Criteria

• When a new framework is created, the source column is correctly populated.
• Pre-existing frameworks have their source back populated.