Add acceptance tests for the password policy framework implementation

[fairclothjm]

Description

This PR

• adds acceptance tests for the password policy framework implementation
• removes the sdkV2 password policy resource
• adds an id field to the base schema because
  • the id attribute was implicitly added in the sdkV2 so we must explicitly add it for existing resources, otherwise its a breaking change for practitioners and
  • it is required for acceptance testing with the sdkV2 package
• writes the id field to state for the Create/Update/Delete operations which is required for backwards compat and acceptance testing

Additionally, we add a placeholder directory structure for new resources and datasources implemented with the TF Plugin Framework:

internal/vault
├── auth
│   └── README.md
├── secrets
│   └── README.md
└── sys
    ├── README.md
    ├── password_policy.go
    └── password_policy_test.go