Add DataSecure flag for group addresses

[farmio]

Add a bool flag to group addresses when DataSecure is used for the address.

[codecov]

Codecov Report

Merging #306 (028e776) into main (e4f8e29) will increase coverage by 0.00%.
Report is 7 commits behind head on main.
The diff coverage is 100.00%.

❗ Current head 028e776 differs from pull request most recent head baf5f79. Consider uploading reports for the commit baf5f79 to get more accurate results

@@           Coverage Diff           @@
##             main     #306   +/-   ##
=======================================
  Coverage   97.31%   97.32%           
=======================================
  Files          21       21           
  Lines        1007     1009    +2     
=======================================
+ Hits          980      982    +2     
  Misses         27       27           

Files	Coverage Δ
xknxproject/loader/project_loader.py	98.18% <ø> (ø)
xknxproject/models/knxproject.py	100.00% <100.00%> (ø)
xknxproject/models/models.py	97.47% <100.00%> (+0.01%)	⬆️
xknxproject/xml/parser.py	94.17% <ø> (ø)