Add 'uri_lowercase' field for stream uri search

Since our 'uri' field was set to not_analyzed it was not available to make a case insensitive search for ES.
This solution expands our already multi-field uri to add the uri_lowercase field which is analyzed by an uax_url_email tokenizer and a lowercase filter.

After that our streaming page will use this field when searching for an uri segment.

Fixes #1028