PHP Roundcube enhancements

What is needed:- Enhance/Upgrade on the login system of Roundcube What is roundcube:- Roundcube is a web-based IMAP email client. Roundcube's most prominent feature is the pervasive use of Ajax technology. Roundcube is free and open-source software subject to the terms of the GNU General Public License (GPL), with exceptions for skins and plugins. What do we need updagraded? Roundcube uses it own framework, and the user logs in using his/her IMAP email credentials. There is a users table but the use of the same is doubtful as the password to the email are not stored in it. We need to create a new system that will have a virtual users system i.e. that is Admin Panel:- • Users CURD • Teams CURD, users can be added to the team and a manager can be assigned to the team. • Team can be part of a larger team. • Email Account Manager, Where an email address is stored along with a password. All server settings are stored in config file as normal roundcube behaviour. • Mapping users and teams to monitor an email account. (Access Control) • Mapping users delete, send email rights on mapped email account (Access Control) • IMAP folders access rights per user and per team • VirtualUser Signature management. • Access to settings for actual accounts and virtual accounts as originally done in roundcube. User to use roundcube:- • Disable user signature update. • Users Setting access only if allowed by ACL • All outgoing email by virtual users to mandatory have its signature. • All users probhited to send email, there email should go automatically in drafts for the manager to approve and send. Manager should choose which signature should the email carry, the users or the managers. Must haves:- 1. Independent Admin panel 2. No breaking of roundcube all plugins available shall work perfectly. 3. Availability of the developer for future enhancements. 4. Works made for hire and IPR Agreement. 5. Demonstratable previous work. 6. Strict timeline adherence.