start-update-interface: implement update manager

Implement the update manager module for the new daemon inheriting from
the Update D-Bus interface. Link with new interface APIs from
item_updater and

start-update-interface: implement update manager

Implement the update manager module for the new daemon inheriting from
the Update D-Bus interface. Link with new interface APIs from
item_updater and software utils. New daemon will continue to exist at
runtime alongwith old flow, until old flow is deprecated and removed.
This change is based on -
https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/65738
https://gerrit.openbmc.org/c/openbmc/docs/+/65739

Change-Id: I0ecbbb8fc5340de7f66f8870ae389b405a2debee
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>

show more ...