S61472 - Initial work to get heatmap into app catalog.
1. Added heatmap to iteration burndown toggle
2. Added legend
3. Refactored to separate iteration progress charts
Renamed iterationburndownminimal to iterationprogress in light of its current state
Renamed files for burndown chart
Deleted iterationburndownminimal directory
Removing old IterationBurndownMinimal specs
Removing labels
bumping appsdk to 1746-cab7380