Fix transform to SQL to escape string values. (#337)

Escape string constants in our SQL files by following the Postgres
documentation about String Constants With C-Style Escapes, see:

  https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS

This format helps guarantee that a single SQL statement in our SQL files are
always found on one-line only, which we use in the apply process to avoid
having to actually parse the SQL files.