Adds SearchResource implementation
Specialized class for authentication config
Integrate ElasticSearch client with SpringMVC bootstrap
Fix crash on missing index fields
Filter documents with index errors
Fix missing context path in document URL.
Fix test case after changing href URL
Fix object owner to value "qucosa"

TODO: This should be determined using API authentication.
Scroll search result to obtain all hits at once
Adds default search field
Add sort order parameter
Removes hard coded mappings and adds field configuration
Handle legacy Solr quoting
Merge branch 'search-endpoint'

Implements /webapi/search resource for legacy Qucosa searching.
Fulltext searching is not yet implemented, but can be added easily
as soon as the final index document structure is defined.