Price sensor unit_of_measurement to ISO4217 and state_class:total add…

[geertmeersman]

…ed for consumption

Description

• price charging point entity: state_class:measurement added
• unit_of_measurement: EUR/kWh instead of €/kWh (not iso4217)
• consumption entity state_class:total added

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Enhancement (changes that improvement of current feature or performance)
• Refactoring (changes that neither fixes a bug nor adds a feature)
• Code style optimization (changes that do not affect the meaning of the code)
• Docs (changes that only update documentation)
• Chore (changes that don't modify src or test files)

Self Check before Merge

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.