Use proper indexed queries for DSL search

Per janusgraph documentation https://docs.janusgraph.org/latest/index-parameters.html strings are indexed as text by default. To use the indexes one is required to use

• textContains: is true if (at least) one word inside the text string matches the query string
• textContainsPrefix: is true if (at least) one word inside the text string begins with the query string
• textContainsRegex: is true if (at least) one word inside the text string matches the given regular expression
• textContainsFuzzy: is true if (at least) one word inside the text string is similar to the query String (based on Levenshtein edit distance)

Atlas uses string search which is suboptimal and leads to significant performance loss. We have observed subsecond queries vs half minute pkus