[FeatureRequest] More action triggers

**Is your feature request related to a problem? Please describe.**
I want to send messages before any of the builds start and send more messages during the process so people not in unity can see what state the builds are at.

**Describe the solution you'd like**
Post-upload actions are great but i want to trigger actions when
- Before starting uploading
- When each step is done (eg: Making builds)