[DE-746] Major update

[maciej-nedza]

• Removed deprecated authentication scheme
• Improved error handling, introduced error templates
• Enabled additional model properties
• Renamed BulkComponentSPricePointAssignment to BulkComponentsPricePointAssignment
• Add query parameters for list subscription group proforma invoices
• Use ProformaInvoiceStatus for list proforma invoices status query parameter
• Added missing fields in the Allocation model
• Added missing 404 errors for subscription components endpoints
• Renamed components price points related models to match the proper camelCase style
• Changed includeNextProformaInvoice param type from String to an enum
• Add enums for proforma invoices and invoices properties:
  • Invoice Discount Source Type
  • Invoice Discount Type
  • Proforma Invoice Discount Source Type
  • Proforma Invoice Role
  • Proforma Invoice Status
  • Tax Source Type
• Remove ProformaTaxBreakout, use InvoiceTaxBreakout instead
• Make Proforma Invoice reuse InvoiceConsolidationLevel and CollectionMethod enums instead of strings
• Remove ProformaInvoiceDiscountBreakout - use InvoiceDiscountBreakout instead
• Add missing fields for ProformaInvoiceDiscount
• Add tests for Proforma Invoices
• Merge proforma invoice and preview proforma, add kind for invoice line item
• Add kind to invoice line item
• Add apply_on_subscription_expiration to Coupon models

[swarmia]

✅  Linked to Task DE-746 · Update the sdks before the release
➡️  Part of Story DE-733 · Release SDKs V2.0 & DevPortal
➡️  Part of Epic DE-677 · Java SDK test coverage increased to 50%
➡️  Part of DE-113 · OneMaxio API