Code move to prevent circular dependency

While implementing https://gerrit.openbmc.org/c/openbmc/bmcweb/+/57932

,
 there has been an issue where there is a circular dependency between
routing.hpp and privileges.hpp. This code move predates this change
to resolve it before implementing the heart of redfish authz.

Circular dependency will occur when we try to use the http verb
index variables in privilege.hpp. If this occurs routing.hpp
and privilege.hpp will co-depend on each other
and this code move prevents this from occuring.

Tested:
bitbake bmcweb
Code compiles (code move only)
Redfish Validator passed on next commit

Signed-off-by: Edward Lee <edwarddl@google.com>
Change-Id: I46551d9fe222e702d239ed3ea6d3d7e505d488c8