Dev index other identifiers for solr searches

Index other external identifiers

https://trello.com/c/5lpinlgD/653-index-other-work-external-identifiers-in-addition-to-dois

Now you can search works based on other identifiers, doing queries like: 

curl -H "Accept: application/orcid+xml" "http://localhost:8080/orcid-pub-web/search/orcid-bio?q=eid:XXX"
curl -H "Accept: application/orcid+xml" "http://localhost:8080/orcid-pub-web/search/orcid-bio?q=issn:XXX"
curl -H "Accept: application/orcid+xml" "http://localhost:8080/orcid-pub-web/search/orcid-bio?q=osti:XXX"