This fixes the following deprecation warning
```
DEPRECATION WARNING: Extra .css in SCSS file is unnecessary. Rename /usr/src/app/app/assets/stylesheets/darkswarm/variables.css.scss to /usr/src/app/app/assets/stylesheets/darkswar
m/variables.scss. (called from _app_views_layouts_darkswarm_html_haml___3990351141569700945_46957256630860 at /usr/src/app/app/views/layouts/darkswarm.html.haml:18)
(...)
```
This way we can tweak the `fill` property of the SVG and style it with
CSS as the documented in the author's repo
(https://github.com/SamHerbert/SVG-Loaders)
> An icon's color can be manipulated by changing the fill attribute in
the SVG file.
The map is displayed using https://leafletjs.com/
To enable Open Street Map go to the Admin -> Configuration -> Content section and click 'Open Street Map Enabled'.
The 'Open Street Map Provider Name' setting can be used to configure different tile providers thanks to the Leaflet-providers extension (https://github.com/leaflet-extras/leaflet-providers)
Some tile providers require an API key, this can provided in JSON format e.g. '{ apiKey: 123 }' in the 'Open Street Map Provider Options' setting.
Each tile provider has their own usage policy so this should be checked before enabling Open Street Map.
The search field for the Open Street Map works differently than searching on Google Maps. It matches producers by their name or address because it was easier to implement instead of matching place names all over the world.
For https://github.com/openfoodfoundation/openfoodnetwork/issues/3491
The spinjs-rails gem provides a CSS3 a spinning activity indicator. This commit removes the gem so we don't have to keep the gem up-to-date and uses the spinning-circles.svg which is used already in other places.
The spinjs spinner can be seen when viewing or editing taxonomies in /admin/taxonomies. It is loaded from the .ajaxStart call in app/assets/javascripts/admin/spree/progress.coffee
To test or restyle this spinner you can change the display property of the #progress element in app/assets/stylesheets/admin/components/progress.scss to 'block'.
