DDF for Heiman Smart siren HS2WD-E (#6400)
DDF for Heiman Smart siren HS2WD-E (#6400)

* Add DDF for Heiman Smart siren HS2WD-E

From issues https://forum.phoscon.de/t/heiman-hs2wd-e-siren-state-alert-always-remains-at-none/2101/22 and https://forum.phoscon.de/t/heiman-warningdevice-ef-3-0-siren-no-battery-and-tampered-status/2346

* Rounded battery level calculation

Rounded battery level calculation
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