Update Audit Log documentation for Embedded Crowd events

In relation to the Audit Log Events documentation, we should clarify which events are audited depending on the user directory type.

Examples:

• We should clarify that the event User created from directory sync (UserCreatedFromDirectorySynchronisationEvent) is only logged for user directories configured as a delegated authentication method.
• Confirm if Group added to user group (GroupMembershipsCreatedEvent) can be triggered from Bitbucket. If not, this should be removed from the document.