API endpoint cluster.put_settings accepts timeout & master_timeout query parameters

Closes #8769
[CLIENT] Add internal liveness action

This commit adds a very lightweight action to the transport
serivce that allows to fetch clustername and the discovery node
from a node. This is used by transport clients to test liveness of
a node without using the nodesinfo API which can be blocking if management
threadpools are busy.

Closes #8763
Merge branch 'master' into fix/8493-systemd-service-file-for-debian
Factor out PID file creation and add tests

This commit factors out the PID file creation from bootstrap and adds
tests for error conditions etc. We also can't rely on DELETE_ON_CLOSE
since it might not even write the file depending on the OS and JVM implementation.
This impl uses a shutdown hook to best-effort remove the pid file if it was written.

Closes #8771
Merge branch 'master' into fix/8493-systemd-service-file-for-debian