display callenge (captcha) for AODAAC downloads
asyncDownloadController unifies behaviour for gogoduck and aodaac
tests for AsyncDownloadController

moved tests from GogoduckController and AodaacController to
AsyncDownloadController
verifying parameters are passed to GogoduckService
rogue clients will be treated as regular clients even if in trustedClients
rename downloadAuth config

 * trustedClients -> whitelistClients
 * rogueClients -> blacklistClients
tidy up groovy syntax all over
Merge pull request #1291 from aodn/aodaac_challenge_captcha

AODAAC challenge captcha