Document and validate web-api constructs

Document and validate web-api constructs

We ditch immutables.org and use interface/builder/record to provide
minimal API footprint change. Any violations are flagged by builder
setter methods.

This forces a rather more thorough change in APIs, but the result is
more worth the churn.

The urlPatterns are check for compliance with Java Servlet
Specification, version 3.1.

JIRA: AAA-233
Change-Id: If65aa0fac7ee7040e89d926bf115b4f124c5b4e2
Signed-off-by: OleksandrZharov <Oleksandr.Zharov@pantheon.tech>
Signed-off-by: Ivan Hrasko <ivan.hrasko@pantheon.tech>
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>