New port -- security/mere-auth: Auth library to be used for mere system interface

Auth library for mere system interface
A library to expose simple api for the auth-aware application to check an user.
Current it support PAM authentication only.

WWW: https://auth.merelab.io/

PR: 241839
Submitted by: Bhuiyan Mohammad Iklash <bhuiyan.mohammad.iklash@gmail.com>