[FEAT] Postgresql adapter for Hangfire

## Feature Request
To be able to use postgresql storage for all related extensions, it would be great to also have a postgresql adapter. In https://github.com/elsa-workflows/elsa-core/blob/main/src/modules/Elsa.Hangfire/Extensions/ModuleExtensions.cs I cannot find this adapter / extension.

### Problem Overview
**Is your feature request related to a problem? Please describe.**
I cannot use the hangfire integration with postgresql.

### Proposed Solution
**Describe the solution you'd like**
Implement an extension to use postgresql as the backing storage.

### Alternative Solutions
**Describe alternatives you've considered**
Use the in memory integration

### Use Cases
**Identify potential use cases**
Everyone who wants to use postgresql will benefit.