Resolve "Make rocketchat test deployment"

Closes #166

See merge request openappstack/openappstack!166

Resolve "Backup and restore instructions"

Closes #152

See merge request openappstack/openappstack!194

Resolve "Let users test their cluster easily"

Closes #441

See merge request openappstack/openappstack!191

Closes: #152

See https://open.greenhost.net/openappstack/openappstack/-/jobs/15079
for an example where the script fails but the CI job still continues

Resolve "Wrong NodeFilesystemSpaceFillingUp prometheus alert"

Closes #446

See merge request openappstack/openappstack!193

Closes: #446

remove unnecessary steps from gitlab ci, checkout correct version of rocketchat chart, check certs of OO and grafana

Resolve "Ignore KubeAPILatencyHigh Prometheus alert"

Closes #385

See merge request openappstack/openappstack!185

define before_tag function here instead of in oas_behave repo

See merge request openappstack/openappstack!189

Merge branch 'oas_behave-1-set-oas-specific-values-in-openappstack-repo' into 166-make-rocketchat-test-deployment

Resolve "Hostname is still too long"

Closes #442

See merge request openappstack/openappstack!188

Resolve "Remove helmfiles"

Closes #408

See merge request openappstack/openappstack!172