This issue is part of the EPIC: Signature process of an initiative #4644

Add actions to admin panel to:

• Generate and download logs of signatures.
• Generate and download lists of signatures in PDF format (take a look at decidim_conferences for this) with:
  • Identifier of the initiative
  • Title of the Initiative
  • Date of start and date of the end
  • Number of Initiatives
  • List of signatures:
    • Identifier of the initiative and title
    • Personal data provided in the signature process
    • Time an date
    • Timestamp
    • Hash (Hash of the last signature + this signature)