Create a service to fill the PDF file

1. GET endpoint

1.1. Document from preparatortest to signertest

1.1.1. preparatortest can download the file

1.1.2. signertest can download the file

1.1.3. signer1 cannot download the file

1.2. Document from preparatortest to signer1

1.3. Security

1.3.1. The user need to be authenticated

1.3.2. Only the signer can download the document