added time and day related evu events (related #38) #248

[Gifford47]

i've added a new attribute SA.EVU_DAYS and a logic which saves the evu days into the mentioned attribute. in the _calc_next_evu_event_minutes(self) is now a new fraction of code which takes care of the days on which the evu is not present. it calculates the "pause" time and adds it to EVU_minutes_until_next_event

Knows Bug: @BenPru currently i get the following error because of wrong types:

  File "/config/custom_components/luxtronik2/sensor.py", line 443, in _wd_txt
    for i in value:
TypeError: 'datetime.time' object is not iterable

NOTE: ive changed _attr_cache: dict[SA, object] = {}`