Add PostgreSQL database support

[samuel-lindgren]

The chart currently lacks PostgreSQL support, which is useful for users who want to:

• Evaluate Cadence using PostgreSQL
• Use Cadence with their existing PostgreSQL database setup

Proposed Changes:

Introduce PostgreSQL configuration options to:

• Deploy Cadence with a new PostgreSQL database
• Connect Cadence to an existing PostgreSQL database
• Add PostgreSQL initialization as a job (potentially in schema-job.yaml).

[CosminL-DEV]

WIP #29 and Schema Job support for Postgresql/Mysql will be in next PR

[CosminL-DEV]

WIP #40 for schema job support