4.2.x master default fixes

[Mbd06b]

This pull request attempts to resolve all the errors and issues I encountered trying to install with the default helm chart with minimal configurations, while trying to respect the original intentions of Michael's helming approach.

• It suggests downgrading your master chart appVersion to 6.4.2 to support the available images closest to the "6.4.x" release
• It removes helm templating syntax in the values.yaml which fixes errors resolving the ... | default .Chart.AppVersion }}" in the image: definition of the templates
• It fixes a pod init error with the postgresdb pod, by implementing a pattern recommended by the postgres error log:

initdb: error: directory "/var/lib/postgresql/data" exists but is not empty
It contains a lost+found directory, perhaps due to it being a mount point.
Using a mount point directly as the data directory is not recommended.
Create a subdirectory under the mount point

By specifying a meaningful subdirectory for data initialization (ie. PGDATA env var) within the mountPath.

This fixes outstanding issues: https://github.com/nemonik/taiga-helm/issues/7

[Mbd06b]

You might be able to test my release with my registry here, I setup this harbor registry in order to package and debug these changes from the current default deployment

helm install myTiagaRelease oci://harbor.ethosengine.com/ethosengine/taiga --namespace taiga --create-namespace -f 
 values.yaml