Resolve "Export django model choices for icons"

Closes #8

See merge request !6

Advances #6

Fix config JS snippet to work with current Iconify

See merge request !5

cf. https://docs.iconify.design/api/config.html#using-iconifyproviders

Configure Renovate

See merge request !1

Add utility function to split string into css value and unit.

See merge request !2

Docs say there are defaults, but there aren't…