Force users to be recently authenticated to view their Profile [#MEM-403]

With this commit, the user must have a recently dropped  (last 20 minutes) SC_GA_LA ('Last Authentication') cookie to access these urls:

https://profile.theguardian.com/account/edit
https://profile.theguardian.com/public/edit
https://profile.theguardian.com/membership/edit

https://jira.gutools.co.uk/browse/MEM-403

cc @adamnfish @Nick-Smith @dbgdngit @JuliaBellis