implement setting admin password

First, admin password comes to spawn method, so we need
to set it there. And there is also additional method
set_admin_passwd.

It should work for containers in any case, for VMs - only
if it's linux and has parallels tools installed. But now
it doesn't work for VM, because waiting for system boot is
broken for VMs. We need to fix that problem first.
change way how glance stores our images

Our images was full VE directories, packed with tar. But
it's not a good solution, because it stores too many information
but really in need to store only root disk data and some
parameters, like ostemplate for containers.

So this patch changes our images format to just ploop.
You can upload ploop to glance with following steps:
1. merge all snapshots
2. set pcs_disk_descriptor to the content of the DiskDescriptor.xml
   file. Line breaks must be removed, because glance API v1 doesn't
   support them
3. set pcs_ostemplate to the ostemplate of the container
4. set pcs_image_name to the name of the image file
5. upload data of the image file to the 'data' of the image
   in glace

Also pcs-glace-tool can be used for uploading images.
Now both pcs-glance-tool and driver support only containers
without snapshots. VM and snapshots support will be added in
consequent patches.
pcs-glance-tool: add method, which finds boot disk

Add method _get_ct_boot_disk, which returns VmHardDisk instance
of the boot disk.
add VM support to pcs-glance-tool

For vm we need to determine correct boot device, since
it can be more than one hard disk.
remane GoldenImageTemplate to PloopTemplate

Now we store only ploop images, not entire VEs,
so rename class accordingly.
split PloopTemplate.create_instance method

Split PloopTemplate.create_instance method into container's
and VM's part, because now it will be almost different.
add VM support to PloopTemplate

Add VM support to PloopTemplate class. For VMs we have
all needed functions in prlsdkapi, so VM create process
includes following steps:

1. Create VM with default config
2. Remove unneded net devices and hard disks, if any
3. Copy ploop into VM directory
4. Add it to VM config
5. Set new hdd as first boot device
Merge <test server>:pcs-nova-driver