Features:
* Add Workout editor (work in progress) (#64)

Development:
* Upgrade jetpack compsose to v1.0.0-beta04 (16f30cf9)
* Update package structure in ui.workout (bb8540df, 2f42fd54)
* Simplify insights layout (7992fce3)
* Other minor changes (8ec5c36f, 840835ac, 256c4495)
