Enable decentral monitoring in runtime (or node)

[elfenpiff]

Brief feature description

When an application crashes, the resources are not yet cleaned up. With #96 we introduced to a mechanism to check if a process is available or has crashed. The Node in #102 shall instantiate a monitor token so that it can be monitored from within other processes.
If the runtime/node is signaled as dead, the decentral cleanup API shall remove all resources of the dead process.