Sector fix for rinning single zone/state

[trevorb1]

Closes #424

Changes proposed in this Pull Request

In this PR I have:

• Updated sector coupling to run single reeds zones or states, as was introduced in PR Implements option to build individual/groups of States/Regions #420.
• Fixed issues with assigning carriers for sector studies was also completed.
• Fixed issue where commercial demand was using residential demand data
• Add EV policy file to master config, as this got missed being added a while ago

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Changed dependencies are added to envs/environment.yaml.
• Changes in configuration options are added in all of config.default.yaml.
• Changes in configuration options are also documented in doc/configtables/*.csv.