Not possible to set add-on properties like instance group properties

[univ0298]

Describe the bug As discussed with @jandubois : https://cloudfoundry.slack.com/archives/CQ2U3L6DC/p1601921603099900 it's not possible to set properties for addons in the Chart YAML, like it is for instance groups. It requires inline operations instead which is harder to use

To Reproduce N/A

Expected behavior It would be helpful to have something like addon_properties section in the chart YAML

Environment N/A

Additional context N/A