This patch:

* Classifies RemoteSecuritySettings as production.
* Add detailed logging controlled by the browser.policies.loglevel pref.
* Generally make RemoteSecuritySettings match other services better.
* Move to hex-encoded hashes to match Kinto.
* Adds RemoteSecuritySettings to blocklist-clients. This may not be the
  permanent home.
* Adds a preference for how many certs to download at once.
* Adds an Observer interface.

    (This makes the tests more predictable, but it also avoids having a
    duplicate call when the full "sync" is called.)

Differential Revision: https://phabricator.services.mozilla.com/D19043

--HG--
extra : moz-landing-system : lando