chore: add documentation to the code

fix(link): make testbenches work in quartus, fix old testbenches

fix(link): check that characters in ilas parser are control characters

ILAS parser did not check that characters are control characters,
error would be encountered if there was R or A non-kout character

feat(data): switch to ILS mode in ilas parser when received non K character in CGS

feat(data): do not reset config when switching from ILS to DATA

feat(link): implement ilas parser

feat(link): add part of ilas parsing

feat(link): add ilas parser declaration