Allow rules engine to batch write to timeline

We need to be able to batch write to timeline from rules engine, for various reasons/use cases:

1. Be able to mark participation to a specific event (in our case, a product change advisory board) in bulk for all our participants instead of having to create the entry manually for all companies.
2. Be able to mark key tech touch engagement completion such as onboarding automatically into timeline as they’re milestones in the customer journey (using the AO Participant object/AO Participant Failed object). 

It seems timeline currently is that unalterable record except by individual CSMs, but we need to be able to write to it as an admin.