Facets prefix/suffix

This module enables an additional processor where you may add a prefix or suffix to the facet result item.

This prefix/suffix can be set per facet with the following two options:

• The prefix and/or suffix value can be inherited from the source field.
• The prefix and/or suffix value can bu custom set.

This module is currently depending on the dev branch of facets: https://www.drupal.org/project/facets/releases/8.x-1.x-dev
Due to this patch: https://www.drupal.org/node/2851851

Will provide a stable version, once it's committed to stable.

- With lot's of help from @borisson_