Update stack_infrastructure_template dynamically in Stack instance

[SamyCoenen]

Expected Result

After changing location, zone or other files the files should be used.

Actual Result

After changing location, zone, sit or other file the old sit keeps being used.

{'time':'2020-05-18 15:16:24,532', 'level': 'ERROR', 'message': '[StackManager] Error with processing task. Error: ''vsphere.brussels.vmw-vcenter-01'''}
Traceback (most recent call last):
  File "/opt/stackl/manager/stack_manager.py", line 46, in handle_task
    (stack_instance, status_code) = self.process_stack_request(
  File "/opt/stackl/manager/stack_manager.py", line 90, in process_stack_request
    merged_sat_sit_obj, status_code = handler.handle(job)
  File "/opt/stackl/handler/stack_handler.py", line 28, in handle
    return self._handle_update(item['document'])
  File "/opt/stackl/handler/stack_handler.py", line 290, in _handle_update
    stack_instance = self._update_stack_instance(stack_instance, item)
  File "/opt/stackl/handler/stack_handler.py", line 98, in _update_stack_instance
    capabilities_of_target = stack_infrastructure_template.infrastructure_capabilities[
KeyError: 'vsphere.brussels.vmw-vcenter-01'

Steps To Reproduce

Potential Causes, Fixes or Additional Information