add logic to verify message signatures
add logic to verify message signatures

once triggered, messages will now be verified and the result of the
verification is sent back to the view to present it.

mailvelope/mailvelope,mommel/mailvelope,mommel/mailvelope,Manouchehri/mailvelope,anthonymiyoro/mailvelope,Manouchehri/mailvelope,linagora/mailvelope,mommel/mailvelope,linagora/mailvelope,linagora/mailvelope,Manouchehri/mailvelope,anthonymiyoro/mailvelope,power12317/mailvelope,power12317/mailvelope,anthonymiyoro/mailvelope,mailvelope/mailvelope,mailvelope/mailvelope