Expose generate_hints Parameter

[daniel-j-h]

On IRC @quiqua just asked:

16:36 < quiqua> Is there a way to disable the generation of hints in node-osrm for osrm.table(options)?

Seems like we forgot to bind the new 5.6 parameter generate_hints with node-osrm.

Here is the upstream pull request: Project-OSRM/osrm-backend#3456

Needs to be added to node-osrm - then it will be possible.