feature: check for "insights" entitlement

Previously, we checked all accounts to see if they had smart
management entitlements.

Instead, check if `ENABLE_SMART_MANAGEMENT_ENTITLEMENT_CHECK` is
enabled first. If so, check for "smart_management" in the
"entitlements" hash.  If it's not enabled, check for "insights".

Once this is disabled in all environments, the flag will go away along
with the smart mgmt entitlement check code.

fix: disable account check for mgmt urls

This commit disables the account check for mgmt urls. I need to also
disable it for openapi.json but will do that in a different commit.
The latter requires more thought wrt backwards compatibility for other
callers.

error gracefully if identity header is not present

We previously were only failing gracefully if the identity header was
not present in the entitlement check code. However, not all applications
use the entitlement check.

This commit adds identity header existence checks to the username
logging and RBAC check.

feature: add ENABLE_RBAC env var

If `ENABLE_RBAC` is set to `True`, rbac checks will be enabled. `False`
will disable.

fix: rename PIT to HSP

We are working to standardize on "HSP" and remove references to "PIT".

feature: add RBAC support

This commit adds support for calling the RBAC service. Clients are
expected to use the view helper.

Parse RPM names with insights library

Previously, we were parsing RPM names using the `split` method. However,
there was a change in the way RPM names were stored in the package
profile, and this way of parsing did not work anymore.

Instead, parse using `InstalledRpm.from_package`. We handle both the old
style (`"0:bash-1.2-3.snes"`) and new style (`"bash-0:1.2-3.snes"`) of
package profile now. If we detect `^[0-9]+:` at the beginning, we strip
off the epoch and send the rest through to `from_package`.

This commit also adds unit tests to kerlescan. The library was tested
via **drift-backend**'s tests before, but we are starting to slowly move
tests over here.

feature: add pit service endpoint

This commit makes kerlescan aware of the pit (historical system
profile) service.

bump baseline service to v1

rename SystemNotReturned to ItemNotReturned

rename exception to make it applicable for both baselines and systems.