Controllable character truncation on Display Fields

The 7.x implementation of character truncation in table output is hardcoded, and also breaks link-to-object functionality in table results (since it truncates the results, stripping tags AFTER the link is created):

https://github.com/Islandora/islandora_solr_search/blob/7.x/includes/utilities.inc#L309-L311
https://github.com/Islandora/islandora_solr_search/blob/7.x/islandora_solr_config/includes/table_results.inc#L48-L51

In an effort to correct this and make character limits/truncation not limited to the 'table' display profile type, I have moved the truncation logic to utilities.inc and made the values field-configurable by the user through the 'Configure' link in the display field list.