This change updates the source structure of the OpenDC frontend to
follow the page structure.

This change updates the topology view in the OpenDC frontend to isolate
the world coordinate space. This means that zooming and panning should
not affect the coordinates in world space (but only in camera space). In
turn, this allows us to remove the dependency on Redux for the camera
controls.

This change enables support for panning the visualized datacenter
topology by using the mouse or holding shortcuts. Previously, this could
only be done through repeated key presses.

This change is a rewrite of the existing OpenDC frontend in order to
migrate to the PatternFly 4 design framework.

PatternFly is used by Red Hat for various computing related services such
as OpenShift, Red Hat Virtualization and Cockpit. Since their design
requirements are very similar to those of OpenDC (modeling computing
services), migrating to PatternFly 4 allows us to re-use design choices
from these services.

See https://www.patternfly.org/v4/ for more information about
PatternFly.

This change updates the OpenDC frontend to use the normalizr library for
normalizing the user topology.

This change splits the App container into separate pages, as a starting
point for removing much of the unnecessary state from Redux.

This change updates the frontend to use the FontAwesome 5 React library
that renders SVG icons as opposed to CSS icon fonts. This migration
resolves a couple of issues we had with server-side rendering of the
previous FontAwesome icons.

This change updates the structure of the OpenDC frontend in order to
improve the maintainability of the frontend.