Generate VERP address for a single/array of recipient addresses

Initially, the extension could handle only the case when the number
of recipients where single. Now it can generate VERP address for an
array of recipients.
Fixed errors with address generation

Bug: 69099
Change-Id: I729f8a4bb1094fee816d4936766cf24762564872
Merge "Generate VERP address for a single/array of recipient addresses"