This improves helmfile-apply with two things:
- Some users had timing-out issues or annoyed by huge output from helm-diff run as part of helmfile-apply on first install. `--skip-diff-on-install` skips running helm-diff for releases being newly installed, so that you can avoid those issues.
- Some users had difficultly or found it not straight-forward to install CRDs and custom resources from separate charts in one helmfile-apply (#1353). The new helmfile.yaml release field `disableValidationOnInstall: true` adds `--disable-validation` to helm-diff only for releases being newly released, which should mostly resolve the issue.
Resolves#1353