Restructure timeseries module

[matthias-wende-frequenz]

What's needed?

Some of the parts should move out of the module because they are not solely related to timeseries.

Proposed solution

Quantities

• the quantity types

Data pipeline

• logical meter
• grid frequency

pools

• battery pool
• ...

Alternatives and workarounds

Leave it as is.

Additional context

https://github.com/frequenz-floss/frequenz-sdk-python/issues/84 https://github.com/frequenz-floss/frequenz-sdk-python/issues/575 https://github.com/frequenz-floss/frequenz-sdk-python/issues/222

[llucax]

Yeah, imho everything that is working with the micrograms should be in the microgrid namespace.

Also I would move actors to their domain namespace, and leave actor for the actor framework stuff. This is also a source of a lot of cyclic imports.

[llucax]

Closing in favor of #575.