Copy into wiki section re #7365

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Update after talk with Anders re #7365

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Tidy wiki description format re #7365

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Shorten wiki summary re #7365

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge remote-tracking branch 'origin/feature/7365_wiki_4_load_instrument_from_nexus'