feat: avoid re-generate if files haven't changed

[Eywek]

Get md5 of each controller files, generate md5 of those md5 + config and store it in the openapi.yaml as an extension (e.g. info.x-hash). If the hash is the same as before, avoid re-generating openapi file.

[Eywek]

If types have been updated we want to update the openapi file, so we can't only use controllers content