Resolve "Upgrade to helm 3.0"

Closes #162 and #396

See merge request openappstack/openappstack!239

That is where we get mariadb and redis from.

Resolve "Apps get installed even when opted-out in enabled_applications"

Closes #551

See merge request openappstack/openappstack!261

Resolve "Host something on oas.your.domain"

Closes #502

See merge request openappstack/openappstack!258

Resolve "Could not find a tag or branch when installing oas-behave"

Closes #524

See merge request openappstack/openappstack!260

Resolve "Overlay filesystem on  local storage mounts"

Closes #550

See merge request openappstack/openappstack!259

This reverts commit bb71f433.

This reverts commit 68f1249a.

This reverts commit 5ce8c1ba.

Resolve "Choose which apps get installed"

Closes #437

See merge request openappstack/openappstack!230

Resolve "Show more debug information in CI"

Closes #449

See merge request openappstack/openappstack!192

Merge branch '547-use-prometheus-and-grafana-helm-charts-instead-of-prometheus-operator' into 'master'

Resolve "Use prometheus and grafana helm charts instead of prometheus-operator"

Closes #547, #548, and #517

See merge request openappstack/openappstack!257

configure loki-stack to add itself to the grafana data sources, fix grafana/prometheus combined config, add some default dashboards