Improve Watt-time plugin

[jmcook1186]

Rationale

After deep diving the current plugin logic, I'm concerned we have inherited some poor design decisions and this plugin should be rebuilt from the ground up. Specifically:

• We provide a single grid/carbon-intensity value for an entire input array regardless of the length or timespan of the array. We could be making an API request per observation or per N observations.
• We have a hardcoded limit of 32 days for an input array. Currently, if the array covers > 32 day period we error out. This is because the WT API has this limit built in. However, we should support longer time series than 32 days, either by making multiple requests or using some fallback.
• The mapping between wt regions and other plugins that return some version of a region (mockobs, importers etc) is complicated and hard to maintain, and the data itself needs auditing and updating.

Implementation details

• Spike on WT as a team and determine the right logic we want to implement
• Write new wt plugin specification
• Build new plugin from spec

Priority

3/5
Out current version is not broken, it just has some unneccessary limits and unuual logic that can be improved.

Size

tbc

What does "done" look like?

tbc

Does this require updates to documentation or other materials??

Yes

Deadline

n/a

Acceptance criteria

tbc

[jmcook1186]

Close by Green-Software-Foundation/if-unofficial-plugins#65

[MariamKhalatova]

tested