This PR modifies what gets added to the history of the shell - instead of adding individual lines, we now add entire SQL queries to the history. If those queries contain newlines, they are converted into spaces when moving up. This should allow for easier skipping back/forth when executing multi-line queries.

This is now the history behavior:

D SELECT
> 42;
-- (press up)
D SELECT 42;

All newlines are removed and converted to spaces.