Refactor postgresql and timescaledb charts

[pvannierop]

Problem

At the moment timescale db functionality is broken:

1. No actual timescaledb image is used.
2. Using the POSTGRES_MULTIPLE_DATABASES mechanism for timescaledb does not work because the init script mechanism breaks the init scripts of the timescaledb docker image

Solution

This PR will create new radar-specific charts for postgres and timescaledb that replace platform logic previously set in the RADAR-Kubernetes (helmfile) layer, specifically the docker image (+version) and initialization logic.

Note

The timescaledb image does NOT support initalization of multiple databases. This restriction will be included in a new version of RADAR-Kubernetes.

[github-actions]

Great PR! Please pay attention to the following items before merging:

Files matching charts/*/values.yaml:

• Is the PR adding a new container? Please reviewer, add it to the models (internal process)
• Is the PR adding a new parameter? Please, ensure it’s documented in the README.md

This is an automatically generated QA checklist based on modified files.

[keyvaann]

LGTM