Streamline template creation flows

Redesign the template creation flows.
Deep scan is not added, because the backend patch of deep scan can't be applied for now.

For creating templates from remote isos, this patch should be merged firstly:
[project-kimchi] [PATCH V5 0/7] support distros

Signed-off-by: Xin Ding <xinding@linux.vnet.ibm.com>