Various helm chart fixes and improvements

[alistairking]

Description of PR

Various fixes and improvements for the helm chart based on deployment in our Kubernetes environment.

Notable changes:

• Prepend release name to Deployment names (to allow multiple releases)
• Split PVC into one PVC per pod (since pods don't need to share data)
• Move frontend user DB to a (new) PVC (to avoid data loss on pod restart)
• Move postgres DB data to a PVC (to avoid data loss on pod restart)
• Allow TLS to be disabled on ingress (our ingress does SSL-termination transparently)
• Allow ingress annotations to be added (e.g., to add traefik annotations)
• Fix bug in frontend ingress name (change backend to frontend)
• Fix bug in ingress configuration: hosts parameter was ignored and host used instead.
• Support extra configuration options for PVCs (to avoid having to modify PVC template directly)

What component(s) does this PR affect?

• Helm Chart

Type

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Docs update
• None of the above

Checklist:

• I have read the contributing guide and my code conforms to the guidelines.
• This change requires a change in the documentation.
• I have updated the documentation accordingly.

[vkotronis]

@alistairking https://semaphoreci.com/slowr/artemis/branches/pull-request-221/builds/1
could you check again the format?

Fix End of Files.........................................................Failed
hookid: end-of-file-fixer

Files were modified by this hook. Additional output:

Fixing artemis-chart/templates/pvc.yaml
Fixing artemis-chart/templates/secrets.yaml

Check the contributing guide and the pre-commit instructions ("Common guidelines").
Pre-commit will fix locally any issues when you commit, and then you need to add its changes and commit again until the checks pass successfully.

@slowr could you check the PR since you have more experience than me on k8? I will also try to install it locally on my laptop.

[slowr]

LGTM! Let's fix the pre-commit hook warnings and go through CI before merging.