Ticket relationships, easy to navigate among tickets

Library Upgrades

• Vaadin 8.7.2, Mybatis 3.5.1

Bug Fixes

• Can not send the email notification to all members in the project
• Not display the permissions when editing the project member
• Display the pretty time against the UTC timezone instead of the user timezone

Improvements & New Features

• [Premium] Can change the border color of action, option or danger buttons
• [Premium] Milestone display the wrong logging time in some special cases
• Support bulk invitations of users
• Minor UI improvements
• Support versions, components relationship in task, and risk
• Support relationship among tickets
• Easy navigating among tickets by ticket key