Create a "common" library helm chart equivalent to Bitnami's "common" helm chart.

For now, Bitnami is releasing all its Helm charts, including the "common" library, under the Apache 2.0 license. It's a good idea to create our own, loosely based on Bitnami's chart, possibly hosted in the `bcgov/helm-charts`repository.

Although we do not currently utilize all the available features, we do have some helper functions we could add ourselves.