Ingest NIDM formatted datasets

[jdkent]

neurovault/NiMARE support NIDM, so should neurostore

[adelavega]

I'm pretty hesitant to invest time into this at all given the scarcity, and that people sue NS-Compose to generate datasets.

I think we can keep the issue but remove any milestone from this.

[jdkent]

converting to a discussion as an idea.