Local storing of cached BIDS data

[arnodelorme]

Recreate BIDS folder structure locally (in the .eegdash-cache folder) and store file names and relative path for all the data associated with a recording in MongoDb "rawdatainfo" field

• raw: sub-001/sess-01/eeg/sub-001_sess-01_tast-test_eeg.set
• rawdependencies: ['fdt', 'dat', 'vhdr']
• channelstsv: sub-001/sess-01/eeg/sub-001_sess-01_channels_tsv (whatever file is there)
• electrodetsv: sub-001/sess-01/eeg/sub-001_sess-01_electrodes_tsv
• eventtsv: sub-001/sess-01/eeg/sub-001_sess-01_tast-test_event.tsv
• eventjson: tast-test_event.json

This relative path can help find the file on S3 or locally in the .eegdash-cache folder.