Add ability for user to customize db.pragma

[MisterPea]

Currently db.pragma are baked into the package:

db = new Database(dbPath);
db.pragma('journal_mode = WAL');
db.pragma('synchronous = NORMAL');
db.pragma('busy_timeout = 3000');Ï

This can be limiting for users that require more durability or need to adhere to a certain level of compliance.
The details of these changes are cataloged here