Ensure that the url for a petition image is stripped of whitespace before saving.
(Leading whitespace causes an exception.)
Mostly code to sync from the CRM to VK. Plus a bit
of refactoring for the VK to CRM code.
Have sync_new_crm_members() and sync_crm_subscription_events() return the
CRM created_at timestamp for the last (most recent) object processed.
Code for and to enable sync_crm_to_vk_worker.rb (which replaces
worker/unsubscribe_poller.rb.