Add wireless link support

[dmcken]

This adds wireless links (not wireless LANs). Looking at the readme this plugin >= v1.1.0 requires netbox >= 3.2.0 anyway so I removed the version checks.

Still to do:

• The wireless link is dashed but wireless links don't have a color on the model, should I assign a particular color (or maybe reduce the opacity) to better indicate its a wireless link?
• Frequencies are on the interfaces, should these be brought in and displayed in the tool tip?

Anything else that you guys might want added.

To try it out instead of netbox-topology-views in the requirements.txt use git+https://github.com/dmcken/netbox-topology-views.git@add-wireless-link-support#egg=netbox-topology-views