Handful of bug fixes

• improvement: allow whereNot contraints for the unique and the exists rules 1bdf5e6
• feat: add useTransaction and useConnection methods 789f038
• improvement: making ddl queries compute the query method and not the pretty printer 7d40daf
• fix: update mysql config type to accept mysql2 as a client 2623e66
• fix: use for of loop to iterate over registered connections bfdf53a

v8.0.4...v8.0.5