Load a project from a postgis DB

[gotjoshua]

I would love to be able to save a project file into the same db as the layers are stored.

Steps which explain the enhancement

1. Open Qfield and see a third button: Open PostGIS Project
2. Choose or add a saved PostGres connection (get list from the auth file)
3. Choose project from the available projects in all accessible schemas
4. Load the project and put it in the list of recently opened projects

Current and suggested behavior

Qfield can already open layers and deal with auth, but there is no way to add projects from post{gres|gis}

Why would the enhancement be useful to most users

Anyone who wants to host their own PostGIS server and do collaborative layer and project editing would be thrilled.

QField Version: 3.4.5
OS and Version: Android 11 OneUI 3.1