detect/analysis: Move globals to engine ctx

detect/analysis: Move globals to engine ctx

Issue: 6239

This commit moves the global variables associated with engine analysis
into the detect engine context. Doing so provides encapsulation of the
analysis components as well as thread-safe operation in a multi-tenant
(context) deployment.

(cherry picked from commit c8615bcd4798a1c53323b4591e787cbf0358811c)