add D5X84YU to Danfoss quirk

[hertleinj]

Bought two of the Danfoss thermostats under the oem named Popp .
Without the updated quirks no updates could be triggered from HA.
After the changes updateing from HA works flawless (at least the last day).
The already working way thermostat -> HA still works.

Popp Danfoss was also already mentioned in #1005

First try more than open for input. Ty.

[codecov-commenter]

Codecov Report

Merging #1148 (5922650) into dev (242d5f3) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##              dev    #1148   +/-   ##
=======================================
  Coverage   80.23%   80.23%           
=======================================
  Files         197      197           
  Lines        5438     5439    +1     
=======================================
+ Hits         4363     4364    +1     
  Misses       1075     1075           

Impacted Files	Coverage Δ
zhaquirks/danfoss/__init__.py	100.00% <100.00%> (ø)
zhaquirks/danfoss/thermostat.py	79.16% <100.00%> (ø)

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[coveralls]

Pull Request Test Coverage Report for Build 1455796401

• 2 of 2 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 80.235%

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Totals
Change from base Build 1449277742:	0.004%
Covered Lines:	4364
Relevant Lines:	5439

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💛 - Coveralls

[MattWestb]

I was trying adding it and the Hive TRV that also shall being the same hard and software but was not getting positive feedback from the user so i was not posing the PR.
If you like you can adding it in the same PR or we doing it then user is asking for it.

zigpy/zigpy#840 (comment)

Well done !!