feat(storage): configurable default paging size

This change add the following options to the config file:

    [limits:storage]
    default_queue_paging = 10
    default_message_paging = 10

So that the default value of the  "limit" URI param is now configurable.

This patch also removes the "actions" cruft.

Implements: blueprint configurable-default-paging
Change-Id: Id38295f1e607226a4259be7744e6ce2d7b6de12e