HED standard support

[yarikoptic]

Summary of items for development (after conversation with HED group, attn @VisLab) to introduce support for HED annotations within DANDI to be done across various components of the platform

• facilitate finalization/release of ndx-events with HED support
• NWB -> _events.tsv export for BEP032 (part of nwb2bids)
• develop sample use case dandisets
  • some from Allen Institute following ongoing
  • add HED to WiP neuropixels BEP032 BIDS dataset from @vandermeerlab (attn @manimoh @mvdm)
  • any other?
• add extraction of HED into dandiset summary stats similarly to how done for NIMAR, see e.g. https://nemar.org/dataexplorer/detail?dataset_id=ds005505

After we have good examples

• add support to neurosift (attn @magland), e.g.
  • navigation of different types of events
  • potentially simple analysis of peri stimuli for different conditions neatly annotated using HED
• add to faceted search (@dandi/archive-maintainers)