Add option to archive from Singlefile

[abbasmahfouzz]

Add an alternate path in the archiving tool creating a WACZ archive from a page saved using Singlefile.

• [x] Add option to upload a singlefile in second step of archiving using a WACZ
• [x] Implement the conversion from singlefile to WACZ (generate WARC, indices, content description, page lists and hashes)
• [x] Make created WACZ files compatible with Wayback Machine replay
• [x] Add signature

•  anonymous signing 
  

•  Domain-Name Identity + Timestamp Validation
  

• [x] Verify that the uploaded file is a Singlefile capture
• [x] Make the WACZ creation more robust (check for missing info...)
• [x] Replace text with translations using keyword
• [x] Add error messages