Support the hashicorp vault database secrets backend

[jessesightler-redhat]

Is your feature request related to a problem? Please describe.
Hashicorp supports both static and dynamic roles in the database plugin: https://developer.hashicorp.com/vault/docs/secrets/databases

Right now, these do not work with the vault plugin when using v2 secrets engine. They do somewhat work with v1, but this causes issues for those of us that use v2 secrets.

Describe the solution you'd like
Implement support, at least for static roles. This would make it easier to support dynamic passwords from the vault.

Describe alternatives you've considered
Use v1 or a manual script instead of the vault plugin

Additional context