Upgrade externally installed Helm charts

[atanasdinov]

• Splits up the Helm chart upgrade flow
• If a chart is deployed via a HelmChart resource, the upgrade is trigged by updating it in-place
• If a chart is deployed via any other means (e.g. manual helm install, Rancher UI, etc.), the upgrade is triggered by creating a new HelmChart resource
  • The repository and version settings are extracted from the release manifest
  • The values are extracted from the previous revision of the installed chart

[ipetrov117]

Code looks good. I left some clarification questions/discussions that once addressed I will be happy to approve.

An additional question (which will probably be answered in the questions below):

1. I am guessing we assume that externally deployed helm charts will be deployed in the same expected namespace as the ones specified in the release manifest?