pkg/mountinfo: Add utility for getting mountinfo
pkg/mountinfo: Add utility for getting mountinfo

This new package provides a struct representing each line from
/proc/pid/mountinfo and a function which returns a slice with
parsed information from that file.

Information from /proc/pid/mountpoint will be used mainly for
checking mountpoint's root and filesystem.

Signed-off-by: Michal Rostecki <82ebf970c69340aebb770c3853be5fd96a3eb584@suse.com>

michi-covalent/cilium,scanf/cilium,scanf/cilium,cilium/cilium,tgraf/cilium,eloycoto/cilium,eloycoto/cilium,cilium/cilium,eloycoto/cilium,cilium-team/cilium,eloycoto/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,eloycoto/cilium,scanf/cilium,tklauser/cilium,michi-covalent/cilium,scanf/cilium,scanf/cilium,tgraf/cilium,scanf/cilium,tgraf/cilium,eloycoto/cilium,eloycoto/cilium,scanf/cilium,tgraf/cilium,cilium/cilium,cilium-team/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium