sqlite reader

[philrz]

In researching #2345, data set we're considering using happens to be stored as an sqlite DB. While the sqlite tools provide JSON/CSV export options that allow the data to make its way into Zed tooling for further shaping/storage/query, @mccanne also correctly pointed out that at some point we could add a native sqlite reader.

[mccanne]

This will be easy with the Go sqllite lib. We just scan all the tables and convert. There is so much sample data out there in sqllite this will be very worth the effort.

[philrz]

A community user asked about this recently in the Zui context (https://github.com/brimdata/zui/issues/2923).