ui: Volume create wizard fix

set next action visibility based on whether a vm is available and
select in vms select step view.
ui: Use date helper to construct the default snapshot name
ui: Fix resolving of api error message

fallback to the default ui response code mapped message if
no message exist (or exists but is empty) within the api response
body.
ui: Volume create wizard style fix

Correct misaligned progress indicator in Volume create wizard (step 3)
ui: VM resize view fix

prevent redudant onClose call to counteract inconsistent resize view
state.
ui: Use cyclades settings to determine the maximum allowed disk size
Update Changelog

include upcoming changes related to

- astakos ui
- astakos admin api
- cyclades ui
cyclades: Fix quota error msg when taking snapshot

Provide a user-friendly message when the user tries to create a
snapshot but does not have enough storage space ('pithos.diskspace'
resource).
cyclades: Validate VM metadata on create/update

* Check for VM max metadata items when updating/creating a single item.
* Check the length of metadata items when updating metadata items.
astakos: Fix a unicode bug in user-add

Fix a unicode bug in snf-manage user-add when the username contained
non-ascii characters.