Add Sightengine as an enrichment service

To help with documentation/quickstart we can create a custom enrichment services and package based on the work Joaquin Garzon Pena has already done. https://github.com/nuxeo-sandbox/image-quality-checker

This service uses sightengine.com and would make the following services available.

nudity,wad,properties,face,type,celebrities,face-attributes,scam,text,offensive