Investigate Spring Security 5.2 upgrade

[sabbyanandan]

Now that we have consumable milestones of Spring Security 5.2, let's study what is coming in the upcoming releases, so we can refactor and adapt to it for consistency.

Specifically, look out for whether:

• we can support JWT tokens
• we can switch to a cleaner OAuth/OIDC model
• migration from Spring Security OAuth to Spring Security is complete or not (if not, what is planned in 5.2 vs. 5.3?)
• from the backend service standpoint, can the UAA integration coexist or if it needs an update also
• we need to plan for deprecations

[sabbyanandan]

Issue moved to spring-cloud/spring-cloud-common-security-config #57 via ZenHub