Output data for HA Core DUC, restructure into more classes

[bouwew]

Changes:

• Change the output to enable the use of the HA Core DUC in plugwise-beta.
• Change state_class to "total" for interval- and net_cumulative sensors.
• Remove all remnants of the last_reset-related code (decided also not to keep in combination with state_class = total as the obtained timestamps are quite inaccurate for at least the legacy P1 and the Plugs, it's sometimes minutes off).
• Restructure: introduce additional classes: SmileComm and SmileConnect

[CoMPaTech]

LGTM, good work

[codecov]

Codecov Report

Merging #100 (6253d31) into main (852ea07) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #100   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            7         7           
  Lines         2248      2235   -13     
=========================================
- Hits          2248      2235   -13     

Impacted Files	Coverage Δ
plugwise/constants.py	100.00% <ø> (ø)
plugwise/__init__.py	100.00% <100.00%> (ø)
plugwise/entities.py	100.00% <100.00%> (ø)
plugwise/helper.py	100.00% <100.00%> (ø)
plugwise/smile.py	100.00% <100.00%> (ø)
tests/test_smile.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 852ea07...6253d31. Read the comment docs.