Add event type information for audit events using AuditEventService in `Group Links`

Problem to solve

Some audit events are named audit_operation. This isn't a descriptive name and makes it difficult to differentiated from other events.

Additional context is available in this epic and in the parent epic.

Proposal

Add a meaningful name for the following events and actions that can be used to differentiate them from other events:

Event	Action	Location
Create group link	Create	file
Update group link	Update	file
Delete group link	Delete	file

Naming should follow the noun_verb format and use the past tense. For example ci_variable_created.

For events created with audit_changes we can pass the event name using the event_type argument.

audit_changes(:email, as: 'email address', event_type: 'email_address_added')

Consider this MR as an example of how to do this.

Implementation plan

1. Add an meaningful event name for the events in the Group Links model listed in the proposal.
   • The name should follow the noun_verb format.
2. Update the associated specs.

Notes

• For instructions on how to setup your development environment.
• For any questions regarding audit events reach out to a member of the compliance group.