Add preliminary calculations fields for 252, 259 and 260

[Guzz-T]

This extension does not affect existing queries on the fields used to date. It simply adds new descriptions that can be queried in addition to the existing ones.

Relates to #180

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
luxtronik
__main__.py	25	25	0%	3–66
datatypes.py	450	1	99%	147
discover.py	58	1	98%	63
luxtronik/cfi
interface.py	175	3	98%	167–168, 256
luxtronik/definitions
__init__.py	208	1	99%	216
luxtronik/scripts
__init__.py	35	5	86%	7–16, 51
discover_shi.py	60	60	0%	8–98
dump_cfi.py	14	6	57%	18–25, 29
dump_shi.py	15	6	60%	21–28, 32
performance_shi.py	63	63	0%	7–89
update_screen.py	105	82	22%	6, 20–41, 46–48, 51–61, 64, 70–75, 78, 81–85, 88–92, 95–97, 100–103, 106–111, 115–116, 119–126, 129–136
watch_cfi.py	32	16	50%	36–47, 50–56, 60
watch_shi.py	33	16	52%	38–49, 52–58, 62
luxtronik/shi
interface.py	337	3	99%	438, 519, 527
TOTAL	2432	288	88%

Tests	Skipped	Failures	Errors	Time
378	0 💤	0 ❌	0 🔥	18.162s ⏱️

[kbabioch]

Do we want to merge it like this, or this this something you want to do before merging it?

[Guzz-T]

I’d like to wait for a reply from @dasSofa to see if the description is correct. Then I’ll merge it and remove the TODO from the description later if everything is in ok and the open points from #180 are done.