Summarize data in raw_data/detailed_channel_info

[gsarma]

We need informative tables of the curated data that we have. Some useful things to know:

Distribution of species the data has been collected from
Which channels already appear in ChannelPedia
Which channels have plots that have already been digitized
Anything else that helps us have a better understanding of this data.

See https://github.com/openworm/ChannelWorm2/blob/master/raw_data/summary_data.md for an example