MFA: Support multiple digest algos at a time
Summary: Marged in kolab_2fa changes from https://git.kolab.org/rRPKa2119c58f6d24533f11064127f356c546d66ef26
Test Plan: ./phpunit
Reviewers: #hkccp_developers, mollekopf
Reviewed By: #hkccp_developers, mollekopf
Subscribers: #hkccp_developers
Differential Revision: https://git.kolab.org/D4932