FE: Move the threat monitoring policies page to Policies sidebar

Why are we doing this work

Threat Monitoring is being updated to be more specific to the monitoring aspects (i.e. statistics, alerts, etcetera) * Additionally, the Policies tab is becoming much larger and complicated as it will be handling many types of policies
Take over the current Security & Compliance => Scan Policies sidebar route and move the Policies tab into it and rename it Security & Compliance => Policies
match all existing functionality of the current Policies tab

Design:

Link	Page	Page w/ modal
#322473 (closed)

frontend Show the Policy List component, on the Security & Compliance => Scan Policies sidebar route by updating the security_policies_list.js (if this is a lot of work, one could create a duplicate security_policies_list.js file, make the changes there, and then conditionally render this file in the policies/show/index file based on the feature flag). Do NOT remove the Policies tab from Security & Compliance => Threat Monitoring becauue otherwise we will be removing the policy tab without giving all users access to the Scan Policies sidebar, which is hidden behind the :security_orchestration_policies_configuration feature flag; we must wait until this feature flag is enabled by default and removed before removing the policy tab (MR: !67419 (merged))
frontend move the Security Policy Project Selector into a modal that is openable on the Security & Compliance => Scan Policies page (MR: !67035 (merged))
backend update the more information link to https://docs.gitlab.com/ee/user/application_security/policies/ (MR: !67496 (merged))
frontend/backend create a new folder/index in the policies route folder load the policy editor component when the user clicks the New Policy button and move new route over to policies_controller. update the breadcrumb for new policy page
backend Rename the Security & Compliance => Scan Policies to Security & Compliance => Policies (MR: !67421 (merged))

Edited Aug 17, 2021 by Alexander Turinske