Add support for uploading NWB to dandi

[t-b]

See https://dandiarchive.slack.com/archives/CMGDETALC/p1615903737000300?thread_ts=1615039924.003300&cid=CMGDETALC.

[t-b]

• [ ] Add menu option for uploading/downloading
• [ ] On upload ask credentials (API key?)
• [x] Rename "NWB" menu to "NWB/DANDI"
• [x] Asked in this thread about web API, see https://dandiarchive.slack.com/archives/CMRM25H8D/p1619209002007000
• [ ] Consider having the analysis browser support multiple file uploads to DANDI
• [ ] Think about versioning. We need to inform users of old MIES versions when they download new stimulus sets that their MIES version is too old. One idea is to add a AnalysisFunctionVersion parameter on NWB export/dandi upload. This is read in the *_Check functions for all PSQ functions. And if the supplied version is larger than the current version we output an error message.

[t-b]

Downloading is done in #979.