Better secrets handling with Pydantic 2

[Andrew-S-Rosen]

When we transition to Pydantic 2 (@munrojm is working on this for much of the MP stack), we should think about a slightly more secure mechanism for storing database secrets both in Jobflow configuration files. This is specifically referring to maggma-based credentials.

My proposed recommendation is to use the secrets management features of pydantic-settings, as discussed here (also see this page). Of course, there's no way of avoiding storing some credential somewhere, but this seems like a slightly better approach. That way, if someone shares their config file with someone else without thinking (or even posts it on GitHub), their credentials won't be directly exposed.

[Andrew-S-Rosen]

Transitioned this to the Jobflow repo. materialsproject/jobflow#451