Add string formats (capitalize, title, upper, and lower)

On the [formatters](https://github.com/benct/lovelace-multiple-entity-row?tab=readme-ov-file#formatting) add support for **string** formatters like `capitalize`, `title`, `upper`, and `lower` this goes on par with the Jinja template filters. Examples on `climate.office_radiator_valve` ```jinja {{ state_attr('climate.office_radiator_valve', 'hvac_action') }} = idle {{ state_attr('climate.office_radiator_valve', 'hvac_action') | capitalize }} = Idle ``` Other Examples ```jinja {{ 'title test' | title }} = Title Test {{ 'uppercase' | upper }} = UPPERCASE {{ 'LowerCase' | lower }} = lowercase ``` Giving us these formatters avoid situations lie this <img width="412" height="178" alt="Image" src="https://github.com/user-attachments/assets/ea33901b-c0ab-40e5-b4f0-419fa557db17" />