document subject search

See merge request !31

document get pseudonym

See merge request !32

Update subject

See merge request !29

-	not actually necessary
-	only relevant for create
-	create instructions mentions that you can correct the spelling

see castellum!1646

see castellum!1697

add admin auth guides

See merge request !30

Refactor guides

See merge request !28

Structure: roles and features

Closes #16

See merge request !26