Add transform function support to sync and sync_render#99

magnetised merged 10 commits intomainelectric-sql/phoenix_sync:mainfrom

53-allow-for-transformation-of-messages-from-the-upstream-server-before-passing-to-clientselectric-sql/phoenix_sync:53-allow-for-transformation-of-messages-from-the-upstream-server-before-passing-to-clientsCopy head branch name to clipboard