Add support for generators and stubs generation

Moving the logic of generators and stubs within the application to avoid assembling too many packages for generating scaffolding.

• test: attempt to fix breaking tests on windows d1bac12
• refactor: update adonisrcfile schema with known directories 2c5fc91
• test: add tests for self implemented helpers b862f25
• feat: add path generation helper methods fbdb569
• refactor: streamline exceptions 4ab44a1
• feat: provide access to stubs manager via application 020c36b
• chore: update dependencies 67491cf
• refactor: cleanup generators code 57d8493
• feat: add support for processing stubs 34f612b
• feat: add generators module 9027101

Full Changelog: v6.4.0-0...v6.5.0-0