Custom shelves from the web interface

[julianstirling]

We already had plans for the community to be able to suggest new devices for the web interface. This works well when there is available hardware that is not currently in our database. However, if we consider the option where someone has a very niche (perhaps DIY, customised, or regionally available) device they want a shelf for. It would be great if they could generate a custom shelf directly in the configurator web interface.

For example the most simple one would be if you select custom you get a form to add the dimensions of the device and it makes a zip tie shelf. We could even add an option where mounting holes for the shelf are specified, but this would be a bit more complex.