libprocessgroup: Add support for task profiles

Abstract usage of cgroups into task profiles that allows for changes
in cgroup hierarchy and version without affecting framework codebase.
Rework current processgroup and sched_policy API function implementations
to use task profiles instead of hardcoded paths and attributes.
Mount cgroups using information from cgroups.json rather than from init.rc

Bug: 111307099
Test: builds, boots

Change-Id: If5532d6dc570add825cebd5b5148e00c7d688e32
Signed-off-by: Suren Baghdasaryan <surenb@google.com>