Solr Support For textContainsPhrase

[criminosis]

Describe the feature: Solr as a Mixed Index Backend doesn't appear to support the textContainsPhrase predicate with predicate pushdown.

Describe a specific use case for the feature: If the Solr backend supported textContainsPhrase it would allow searches like g.V().has('vertex_label', 'text_field', textContainsPhrase('unicorn horn')) to be accelerated with predicate pushdown to Solr.