Support configurable OAuth scopes and prompt=consent for granular authentication

[darwintantuco]

Add support for MYOB's granular SME scopes, prompt=consent, and direct company file selection via businessId

• Allow custom scope at client initialization or per-call (defaults to CompanyFile for backward compatibility)
• Add force_consent: true option to include prompt=consent in the authorization URL
• Add set_company_file_from_business_id to set the company file directly from a businessId GUID without calling the company file listing API

All changes are backward compatible.

References

• https://developer.myob.com/api/myob-business-api/api-overview/scopes/
• https://developer.myob.com/api/myob-business-api/api-overview/authentication/