[Backend] SPP Audit event - CRUD operation is performed on an exclusion

Problem to solve

Security teams need to be able to audit anytime an exclusion is created, updated, or deleted for secret push protection, so they have visibility into potential secrets that may be allowed to be pushed.

Proposal

• Add an SPP audit event when a new exclusion is created.
• Add an SPP audit event when an exclusion is updated.
• Add an SPP audit event when an exclusion is deleted.