anchor.diff:  `rememberMe.encryptionKey`
   | any string +
   (in prod, a random UUID each time)
  -|Encryption key is used to encrypt the rememberMe user/password.  +
  -
  -Apache Isis leverages link:http://wicket.apache.org[Apache Wicket]'s rememberMe support which holds remembered
  -user/passwords in an encrypted cookie.
  +|Encryption key is used to encrypt the rememberMe user/password.
  +
  +Apache Isis leverages link:http://wicket.apache.org[Apache Wicket]'s rememberMe support which holds remembered user/passwords in an encrypted cookie.
   
   If a hard-coded and publicly known value were to be used (as was the case prior to `1.13.0`), then it would be possible for rememberMe user/password to be intercepted and decrypted, possibly compromising access.
   This configuration property therefore allows a private key to be specified, baked into the application.
  
positive.code: ----
  isis.viewer.wicket.themes.initial=Darky
  ----
  
  The end-user can also be given the choice of changing the theme:
  
  
negative.code: `rememberMe.cookieKey`
  | ascii chars +
  (`_isisWicketRememberMe_`)
  |Cookie key holding the (encrypted) 'rememberMe' user/password.
  There is generally no need to change this.
  
  Valid values as per link:http://stackoverflow.com/a/1969339/56880[this StackOverflow answer].
  
  