kubevirt_vm: Allow to specify template spec

By allowing to specify the template spec unnecessary abstraction is
avoided.

The following module args are replaced by the 'spec' arg:
  - termination_grace_period
  - interfaces
  - networks
  - volumes

Signed-off-by: Felix Matouschek <fmatouschek@redhat.com>

examples/play-create-min.yml

@@ -0,0 +1,8 @@
+- hosts: localhost
+  tasks:
+    - name: Create VM
+      kubernetes.kubevirt.kubevirt_vm:
+        state: present
+        name: testvm
+        namespace: default
+        running: no