Upgrade to Alpine 3.13, Migrade to lmdb database

Deployment gh-pages-v3.0.0

Fixed a few minor issues

These were mostly issues relating to helthcheck in
`Dockerfile` and the helm chart.

Deployment gh-pages-v2.2.2

Add metadata to helm chart

New: Add Gmail OAuth2 support

The biggest improvement of this release is the support for
Gmail OAuth authentication.

Among other changes, the following improvements have been made:
- better support for healtcheck in the helm chart
- `Dockerfile` now includes the `HEALTCHECK` line for docker deployments
- the possibility to read password from files instead of environment
  variables

Deployment gh-pages-v2.2.1

Deployment gh-pages-v2.2.0

Fix gh-pages deployment

Helm chart and fixes