corosync config parser: move to hash format

corosync config parser: move to hash format

The old parser itself was simple and easy but resulted in quite a bit
of headache when changing corosync config sections, especially if
multiple section levelsshould be touched.

Move to a more practical internal format which represents the
corosync configuration in hash

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>