Add tutorial for DynamicTableRegion and Linked Tables

[oruebel]

It would be useful to have a tutorial dedicated to DynamicTableRegion and how to use to: 1) link to metadata stored in tables, and 2) link between tables (similar to a foreign key in a database). This tutorial should cover:

• Creating DynamicTableRegions
• Using DynamicTableRegion as column in a DynamicTable
• Interacting with tables that contain DynamicTableRegions
• Constructing table hierarchies and the convenience functions available in hdmf.common.hierarichaltable

This issue has been identified as part of PR https://github.com/hdmf-dev/hdmf/pull/645 and the functionality is being used in PyNWB as part of the ICEphys metadata tables defined in https://github.com/NeurodataWithoutBorders/pynwb/pull/1383

Checklist

• [X] Have you ensured the feature or change was not already reported ?
• [X] Have you included a brief and descriptive title?
• [X] Have you included a clear description of the problem you are trying to solve?
• [X] Have you included a minimal code snippet that reproduces the issue you are encountering?
• [X] Have you checked our Contributing document?

[mavaylon1]

This exists in the tutorials. https://hdmf.readthedocs.io/en/dev/tutorials/plot_dynamictable_howto.html#sphx-glr-tutorials-plot-dynamictable-howto-py