Refactor plugin management:
- support multiple plugins per executable
- support restarting a plugin process in the event it terminates
- simplify plugin lifecycle management by using separate managers for
each scope (server vs backup vs restore)
Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>
The main Ark code was hard-coding specific support for AWS, GCE, and
Azure volume snapshots and restores, and anything else was considered
unsupported.
Add GetVolumeID and SetVolumeID to the BlockStore interface, to allow
block store plugins to handle volume snapshots and restores.
Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>
