KEP-5823: Pod-Level Checkpoint/Restore

Co-authored-by: Adrian Reber <areber@redhat.com>
Co-authored-by: Peter Hunt <pehunt@redhat.com>
Co-authored-by: Andrey Velichkevich <andrey.velichkevich@gmail.com>
Co-authored-by: Viktória Spišaková <spisakova@ics.muni.cz>
Co-authored-by: Filipe Augusto Lima de Souza <fals.xp@gmail.com>
Co-authored-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
Co-authored-by: Fabricio Voznika <fvoznika@google.com>
Co-authored-by: Kevin Hannon <kehannon@redhat.com>
Co-authored-by: Mike Brown <brownwm@us.ibm.com>
Co-authored-by: Tim Allclair <tallclair@google.com>
Signed-off-by: Radostin Stoyanov <radostin.stoyanov@eng.ox.ac.uk>