[FEATURE]: Elapsed stage time should be saved by stage

[shapeseas]

User Story

As an experiment designer, I want to set the time elapsed by stage. When I switch the stage to another one and back, I want the time elapsed to stay.

Feature description

Potentially implement the time elapsed in the saved stages in local storage like the stage refs/dependencies.

What would this feature enable?

Editing an experiment would be easier

Priority

Convenience for researchers