XD-2119,XD-2143,XD-2144

* Add 'spring-boot-starter-security' as a dependency
* Set up the admininstration and management endpoints as insecure by default
* Unit tests for SSL
* Unit tests for security enablement
I think we need to add these properties along with other related configuration properties (user, password, realm etc.,) from `org.springframework.boot.autoconfigure.security.SecurityProperties` into servers.yml for externalized configurations to the end user.