Add eID authentication and PDF handling endpoints

[APayerl]

Rename HelloController to ApiController and add new endpoints for PDF validation, signing, viewing, and change requests.

• ApiController

  • Add endpoint /file/{fileId}/sign/{eIdSolution} for PDF validation/signing.
  • Add endpoint /file/{fileId}/view for viewing PDFs.
  • Add endpoint /file/{fileId}/request-changes for requesting changes to PDFs.
  • Add endpoints for BankID and FrejaID validation.

• ValidationService

  • Create a service to handle BankID and FrejaID validation logic.
  • Implement methods for validating BankID and FrejaID.

• PdfService

  • Create a service to handle PDF viewing, validation/signing, and change requests.
  • Implement methods for viewing PDFs, validating/signing PDFs, and requesting changes to PDFs.

• ValidationRequest

  • Create a model class for validation requests.
  • Define properties for user information and eID solution.

• PdfRequest

  • Create a model class for PDF requests.
  • Define properties for file ID and request type.

• application.properties

  • Add configuration properties for BankID and FrejaID.

• SecurityConfig

  • Create a security configuration class to handle eID login.
  • Implement security settings to ensure no endpoint is visible without eID login.