Investigate if plugins actually need to be behind a proxy

[ray-millward-tessella]

Description:
We need to establish whether a proxy for the plugins is needed or will single SPA load them from different domains anyway. The expectation is that CORS will be a problem and this is the reason for using an API proxy/gateway - but this needs to be confirmed.

Acceptance criteria:

• Establish if a plugin from a different domain can be loaded (this means it will have to be hosted somewhere - probably an openstack machine)