Add Ballast min + max level entities

[TheJulianJES]

TODO: Translations in HA.

Proposed change

This adds minimum level and maximum level entities for the Ballast cluster. This is used by dimmers.

Additional information

Diagnostics for the Ubisys D1 dimmer will be added to test this.
We'll need to add translation keys to HA.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.49%. Comparing base (5576445) to head (de45663).
⚠️ Report is 1 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #659   +/-   ##
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  Coverage   97.48%   97.49%           
=======================================
  Files          62       62           
  Lines       10897    10917   +20     
=======================================
+ Hits        10623    10643   +20     
  Misses        274      274           

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[TheJulianJES]

There's a minimum_level translation key with "Minimum load dimming level" as the translation in HA for the Inovelli devices: homeassistant/components/zha/strings.json#L731-L733

I think minimum_dimming_level with "Minimum dimming level" as the translation makes more sense. So, that's what we should add to HA IMO. We can change the Inovelli one in the future (if it has the same meaning – but if so, why didn't they use the Ballat cluster then?)

[TheJulianJES]

Confirmed to work with Ubisys D1 dimmer. I'll add diagnostics dumps for all Ubisys deviecs in a follow-up PR when the quirks bump and all relevant ZHA entity changes are merged.