This commit adds a new starter named spring-boot-starter-shell-crsh and auto configuration support to embed a system shell within Spring Boot applications.
The embedded shell allows clients to connect via ssh or telnet to the Boot app and execute commands. Commands can be implemented and embedded with app.
For sample usage see spring-boot-samples-actuator.
Previously the management endpoint filter was applied to all requests
if the user had disabled security.management.enabled, but since it
had no security applied it was letting all requests through.
The fix was to explicitly exclude the whole enclosing configuration
and carefully ignore the management endpoints in the normal security
chain.
Fixes gh-100.
