Usability Improvement: Improved naming for devices, entities and states + Multi-Language support (DE for now)

[jwiesel]

Breaking change

No breaking change

Proposed change

Replace register names by wording used in Venus OS and enable multi-language support for Victron devices, entities and their states.

• Translations have been taken from Venus OS 3.5 as far as possible (GUI v2). Missing ones have been named/translated based on best guess. Source: https://github.com/victronenergy/gui-v2/blob/main/i18n/venus-gui-v2_de.ts
• Major entity types which I could test in my setup have been translated to EN (default for everyone) and DE.
• For those which are not yet translated the former application logic still applies (using the register names with blanks instead of underscores)

Observations independant of this PR (will check/create separate tickets):

• Some entity states have enums in const.py, but still show numeric values. These will start working, when the enum works correctly (see also #320)
• entities of type "binary_sensor" are also created as "sensor" (duplicate entities)
• entities of type "button", "number", "select" and "switch" are only created as sensors (see also: #325 )

--> Translations have already been created for all entity types and duplicates (translations in type sensor) can be removed when the observations above are fixed.

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [ ] New integration (thank you!)
• [x] New feature (which adds functionality to an existing integration)
• [ ] Deprecation (breaking change to happen in the future)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [ ] Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue: #310
• Link to documentation pull request:

Checklist

• [x] The code change is tested and works locally.
• [x] There is no commented out code in this PR.
• [ ] The code has been formatted using Ruff (ruff format custom_components/victron)