amazon-cognito: init

amazon-cognito: setup

ok

tests

wip sign out

aws sdk

initial commit for group verification feature

some extra tests

empty string slice, not string

additional cognito provider test

extra provider tests

add new tests, and move to options_test.go file

fix cognito validategroup tests

create separate mock admin files

minor edits

remove some comments

couple small improvements

amazon mock admin

changes following review

remove unnecessary method

fixed tests following on from review changes

some updates from review

fix struct name in tests