Re-enable debug logging for plain HTTP connections
CSRF token must be sent using Alfresco-CSRFToken header, not Alfresco-CSRF-Token
Add default timeout of 5 mins (300s) to the client, can be overidden when instantiating the client if required
Externalise CSRF token name, remove debug statements
Add a timestamp prefix to the 'export' container name when we create it

This allows us to still do exports in the future if an old 'export' container was left over (since the treenode webscript no longer returns any children for the export container, so the delete-if-already-present behaviour for ACP files does not work)