vm-rename: Update API.md for vm rename

Add a PUT method to VM resource and allow 'name' attributes to be updated.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
vm-rename: Update controller

Update controller and json schema to support vm rename.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
vm-rename: Update model for vm edit

Classify vm attributes edit for 2 kinds:
1. live update attr: Attributes updated with libvirt api.
2. static update attr: Attributes updated with re-define xml, for running vm,
   only take effect on next boot.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
vm-rename: Update mockmodel for vm edit

Add mockmodel support for vm rename.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
vm-rename: Update testcases for vm-rename

Updated testcases for model and mockmodel for rename.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>