BIG file rearrangement

Move stuff out of ./targetd script into targetd/*.py

Add scripts/targetd (very simple)

Signed-off-by: Andy Grover <agrover@redhat.com>
Change handling of pools config parameter

fs and block pools are totally separate, so define them in separate lists
block_pools and fs_pools.

Still allow old 'pool_name' entry in configfile, add it to block_pools.

Change block/fs to not look at main.config dict, but save off what they
need in their initialize method.

Tidy up some methods in fs.py

Signed-off-by: Andy Grover <agrover@redhat.com>
Add sample targetd.yaml

Signed-off-by: Andy Grover <agrover@redhat.com>
Return bg.uuid in block_pools

block_pools and fs_pools still aren't hooked up to anything yet, fwiw.

Signed-off-by: Andy Grover <agrover@redhat.com>