expand 2FA documentation

See merge request !77

inspired by https://docs.mpcdf.mpg.de/faq/2fa.html

Add example for totp apps

See merge request !76

document two factor authentication

See merge request !75

change "attribute" to "recruitment attribute" in UI

See merge request !74

fix typo

See merge request !72

see castellum!1941

document study approval issue

See merge request !70

add guide for resetting user tokens

See merge request !71

describe study diff view

See merge request !69

see castellum!1861

Clarify two step process for managing recruitment consent

See merge request !66

rm settings TODO

See merge request !68

was added in !40

change security position in the navigation

See merge request !67

-	should come after features (I first want to know what this is)
-	roles and features should be together as they are the entrypoints to guides

Attribute descriptions

See merge request !60