[docs] apply sphinx-lint to docs

This change corrects the detected sphinx-linit issue in the existing
docs and updates the contributor devstack guide to call out
required and advanced.

mostly the changes were simple fixes like replacing the configurable
default rule with explict literal syntax `term` -> ``term``

some inline Note: comments have been promoted to .. note:: blocks
and literal blocks ::  have been promoted to .. code-block:: <language>
directives.

Change-Id: I6320c313d22bf542ad407169e6538dc6acf79901

doc/source/architecture.rst

@@ -285,7 +285,7 @@ Audit and interval (in case of CONTINUOUS type). There is three types of Audit:
 ONESHOT, CONTINUOUS and EVENT. ONESHOT Audit is launched once and if it
 succeeded executed new action plan list will be provided; CONTINUOUS Audit
 creates action plans with specified interval (in seconds or cron format, cron
-interval can be used like: `*/5 * * * *`), if action plan
+interval can be used like: ``*/5 * * * *``), if action plan
 has been created, all previous action plans get CANCELLED state;
 EVENT audit is launched when receiving webhooks API.