Refactor Shiro/HTTP integration

Refactor Shiro/HTTP integration

ShiroFilter is designed to work with EnvironmentLoaderListener, both of
which are designed to work with web.xml.

We are in programmatic-land, hence the indirection through
ServletContext lifecycle is completely unnecessary and actually is
hurtful, as we cannot smuggle WebEnvironment through OSGi HTTP
Whiteboard -- it requires String properties when coupled with
ServletContextHelper.

Here we create a much more direct connection, where AAAWebEnvironment
is eagerly-initialized and it is passed directly to AAAShiroFilter. This
allows us to use AbstractShiroFilter only without having to dance around
init() methods -- and eliminate binding to to static SecurityManager
wiring as well.

JIRA: AAA-225
Change-Id: Id3990dd533b5e60f3781f9e4cdc3114163ecb931
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>