Add higher-level function for firmware version

[gerw]

Closes #128

[github-actions[bot]]

Coverage Report

File	Stmts	Miss	Cover	Missing
luxtronik
__init__.py	181	131	28%	39–51, 73–77, 80, 84–89, 93–97, 108–111, 119–121, 128–130, 137–139, 146–148, 157, 165–167, 170–173, 176–179, 182–198, 201–215, 218–234, 237–251, 255–257, 261–262, 266–267, 278–280, 283, 286, 289, 292, 295–298, 301–304
__main__.py	21	21	0%	3–49
datatypes.py	275	1	99%	82
discover.py	40	34	15%	21–69
luxtronik/scripts
dump_changes.py	44	44	0%	5–85
dump_luxtronik.py	27	27	0%	5–52
TOTAL	675	258	62%

Tests	Skipped	Failures	Errors	Time
122	0 :zzz:	0 :x:	0 :fire:	0.721s :stopwatch: