Three conditions must be met for the console to be enabled:

 - H2 is on the classpath
 - The application is a web application
 - spring.h2.console.enabled is set to true

If spring-boot-devtools is on the classpath, spring.h2.console.enabled
will be set to true automatically. Without the dev tools, the enabled
property will have to be set to true in application.properties.

By default, the console is available at /h2-console. This can be
configured via the spring.h2.console.path property. The value of this
property must begin with a '/'.

When Spring Security is on the classpath the console will be secured
based on the user's security.* configuration. When the console is
secured, CSRF protection is disabled and frame options is set to
SAMEORIGIN for its path. Both settings are required in order for the
console to function.

Closes gh-766