Bugs/#6363

Third commit for bug #6363 with all unit tests successful + updated (reference-repository - unnecessary nodes files in data dir)

Second commit for bug #6363 with a large part of unit tests successful + updated reference-repository

[ui] Handle grouping bugs, when groupings with only one item are not given a grouping header ; do minimal corrections to be able to submit a job ; might be able to deploy an environment with this version

[development] document the possibility of getting the current user from environment if header not defined to help with development

[development] add possibility of getting the current user from environment if header not defined to help with development

Handle cases in quick-start where grouping compacted away pieces of hierarchy because only one node conforms to query. Move code that could be put in common with node.js in exhibit