Ability to set the fuzziness' edit distance when using text predicates in janusgraph

**Describe the feature:**
When using text predicates with an index backend in janusgraph, currently there is no way to set the fuzziness' edit distance. Having that control would help a lot when using it in a search implementation.

**Describe a specific use case for the feature:**
There could be different type of nodes in where search needs to be more precise in one of them while it might not be the case for the other one. In these situations, having the control of the fuzziness' edit distance would make it much more flexible.

No files, tests, or specific index backend are named. Start by tracing how text predicates are translated for index backends and determine which predicate and backend APIs would need to carry an edit-distance setting. Done should include a defined interface for choosing the fuzziness distance and coverage for the affected backends.

Written by the indexing model from the issue text.