request: extract brain area metadata

Based on usage feedback from NeuroDataReHack and from personal experience, searching for brain area is currently a bottleneck. @neurovium also included search by brain area in his search specification document.

Currently, brain area is required for some modalities, but it is buried. It is not currently extracted into asset or dandiset metadata, and requires reading individual NWB file contents. It is also in different places for different modalities.

Searching for brain area can therefore take a long time, particularly in datasets that have many assets. For the IBL dataset, we have been able to get this time down to 8:26 using LINDI (see [discussion](https://github.com/NeurodataWithoutBorders/lindi/issues/85#issuecomment-2239965018)), but that's still not great. It would be much better to pre-extract this metadata, and provide it as asset and dandiset metadata, which would make searching much faster on the user side. It would also allow us to register terms against ontologies and controlled vocabularies and run analyses on the types of brain areas recorded.

Specifically:
1. Modify the Dandiset and Asset metadata to include brain area
2. Modify the CLI to extract this information from the NWB files
3. Modify the NWB Inspector to promote including this information
4. Modify the DLP to display this information