add delete single Document from lucene via api call

[allixender]

due to the incremental updates indexer we might keep old documents in the lucene index. This is good for on-going updates of the index, and we don't need throw away the complete index.

In order to delete from our SMART CSW we should consider add delete single Document from lucene via api call instead of the refreshCatalogue call.

lucene docs: https://lucene.apache.org/core/4_0_0/core/org/apache/lucene/index/IndexWriter.html#deleteDocuments(org.apache.lucene.index.Term)

deleteDocuments(Term) respectively deleteDocuments(new Term("id",id))

[allixender]

testing needed, to be confirmed working