[Feature Request]: Consolidate Tariffs to support Meters and EaaS alike

[dmohns]

Preflight Checklist

• I have read the Contributing Guidelines for this project, if it exists.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Problem Description

Currently, Tariffs are tightly coupled to Meters. However, in Energy-as-a-Service use cases similar concepts are deployed as customers pay "per day" or "per kwh".
Similar, to Meter Tariffs users of EaaS may wish to define a Tariff once, and then use it for multiple customers.

This is a follow up to: #1403

Proposed Solution

Expand the Tariff abstraction to allow Tariffs to be Meter as well as EaaS or others.

Also, adapt changes added in: #1403

Alternatives Considered

N/A

Additional Information

No response