Provide option to order the release of the application parent chart as compared to the subcharts

**Is your feature request related to a problem? Please describe.**
n/a

**Describe the solution you'd like**
The default behavior today is deploy the parent chart after all subchart are deployed and their dependencies are satisfied. In some cases it would require the parent chart to either go in parallel with the subcharts or before the subcharts are deployed. Provide a field in the `ApplicationSpec` that allows users to specify the order of deployment.

**Describe alternatives you've considered**
n/a

**Additional context**
Add any other context or screenshots about the feature request here.