Mute javac unsafe warnings about OsvSystemClassLoader.java

Makes this go away:

  Note: io/osv/OsvSystemClassLoader.java uses unchecked or unsafe
  operations.  Note: Recompile with -Xlint:unchecked for details.

Unfortunately javac does not recognize statement level suppressions
like this:

  //noinspection unchecked
  return (T) method.invoke(target, args);

I need to switch to more coarse grained suppression on method level:

  @SuppressWarnings("unchecked")

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Allow interrupting java apps from CRaSH SSH shell

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Configure java.util.logging -> slf4j bridge for mgmt app

I dismissed the idea to configure the bridge in default JVM
configuration because having a default like this would force
all apps to use particular slf4j-api version.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Copy default java.util.logging config from JDK

Currently all log messages are silently ignored,
which is probably not what we want.

The default JDK config logs on console.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>