ethtool: New component to query and control NICs driver and hardware settings

ethtool can be used to adjust NIC settings, such as e.g. interrupt
coalescing and various others. It usually requires root to do so.

However regular users can query NIC settings via ethtool just ok.

This way upcoming neotest SR will use it to query/display NIC setting
which are essential to get good networked latency and automatically
produce warnings if it is not.

component/ethtool/buildout.cfg

+# ethtool - query or control network driver and hardware settings
+# https://www.kernel.org/pub/software/network/ethtool
+[buildout]
+parts   = ethtool
+
+[ethtool]
+recipe  = slapos.recipe.cmmi
+url     = https://www.kernel.org/pub/software/network/ethtool/ethtool-4.11.tar.xz
+md5sum  = 16d38f4ebe23e44f96f7d8b38ed3652c