build: change codegen to move generated files to src/generated

[ctran88]

What's New?

• extension of refactor: move source code to src directory #102 to also update the codegen script to move generated code into the src/ directory
• ran ./generate.sh openapi.json (successfully runs in repeated executions)

Screenshots (if appropriate):

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have manually tested my code thoroughly
• I have added/updated inline documentation for public facing interfaces if relevant
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing integration and unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Additional context

[vanessa-passage]

Changes look good.

Same curiosities as the other. I'd love to learn more about this SDK and probs you may have faced that prompted these changes. This is just for my own knowledge.

[ctran88]

Changes look good.

Same curiosities as the other. I'd love to learn more about this SDK and probs you may have faced that prompted these changes. This is just for my own knowledge.

this was really just structural. nothing functionally changed or caused the need for this change other than conforming to a common directory structure. in presenting a library, there's no real distinction to be made between "custom" and "generated" code other than for our own sake, so i thought it'd be better to organize it like a typical php project with a src and tests folder at the root and flattening out the generated code structure a bit as well