System restart support

__DO NOT MERGE -- must occur in unison with several other repos__

These changes are part of the broader system restart support. On a high level, the following changes were made to ceiclient:

- Add new commands for managing PD system boot state
- Add new ``process-definition sync`` command to support synchronizing PD process definitions with existing ones (from a prior launch)
- Rework ``process schedule`` command to support scheduling by process definition name