Support download of sqlite database

[hwine]

dataset-lite is great for pointing at a various files and then being able to query across multiple tables. All the specialized commands to load the different tables is handled.

While one can download json or csv results of a query, there doesn't appear to be a way to download the entire SQLite database.

I have users who are comfortable running SQLite queries from the command line, but not necessarily up on the process to download multiple files, then import them into a single SQLite db. Being able to download the created SQLite database.