Dandi

Provides interfaces for a full cycle of dandiset preparation,
registration, upload, and download.

Added
- caching of read metadata and validation results for .nwb files.
Typically those take too long and as long as dandi and pynwb
versions do not change -- results should not change.
Set `DANDI_DEVEL` variable to forcefully reset all the caches.
Changed
- DEVELOPMENT.md provides more information about full local
test setup of the dandiarchive, and description of
environment variables which could assist in development.

Added
- `organize`: organize files into hierarchy using metadata.
ATM operates only in "simulate" mode using .json files dumped by `ls`
Changed
- various refactorings and minor improvements (docs, testing, etc).

Improvements to `ls` and `upload` commands

Added
- `ls`: include a list (with counts) of neural datatypes in the file
- `upload`:
- ability to reupload files (by removing already existing ones)
- ability to "sync" (skip if not modified) to girder based on mtime
and size
- CI (github actions): testing on macos-latest
Changed
- removed `hdmf !=` statement in setup.cfg to not confuse pypi.
Fixed
- `upload` - assure string for an error message
- mitigated crashes in pynwb if neural data type schema is not cached
in the file and requires import of the extension module. ATM the
known/handled only the `AIBS_ecephys` from `allensdk`