core: Add storage space validator

Use the storage validator to validate if there is enough space in the
storage compared to the threshold.
The validator should replace the use of StorageDomainSpaceChecker.

Change-Id: I097965d6362bd54d12860d5409f5c14d569a8968
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use storage validator when adding a new VM.

Use storage validator instead regular check when adding a new VM.

Change-Id: I6ee28506dec042fe60e9691d41458ad54a83b2f0
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use storage validator when validating move or copy.

Use storage validator instead regular check when validating space
requirements in the CDA phase.

Change-Id: I01980de86ed445d397f12ff9c471974d1cb5c44d
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use storage validator when validating add disk.

Use storage validator instead regular check when validating space
requirements in the CDA phase.

Change-Id: I8bb5101600aa22271529fb72fb33b2031ee81f83
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use storage validator when adding template.

Use storage validator instead regular check when validating space
requirements in the CDA phase.

Change-Id: If36ba750308adb2751a02738f66816fb097fe93e
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use storage validator for images handler.

Use storage validator instead regular check when validating space
requirements in images handler functionality.

Change-Id: I212da7c8d1042e54eafaa2e2367081dd1315e003
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
 core: Use storage validator on Live Migrate disk.

Use storage validator instead regular check when validating space
requirements in the CDA phase.

Change-Id: I116f12c0d4c05bd03f0f42009b4727fbd6b71420
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Use validate instead of using space checker.

Use validate instead storage domain space checker for all the rest of
the commands which use validation for storage free space.

Change-Id: I2efe75b59a0890c3349b9927e677a4eac3323e9a
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
core: Remove storage domain space checker

Removing storage domain space checker since the storage domain validator
should replace its functionalities.

Change-Id: I0de49928c667658ccfb1dda1d6573479b2e559ec
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>