Rewritten feature pages

Rewrote the public feature pages for Books, Calendar, Contacts, Design, Documents, Forms, Idea Workspaces, Image Converter, Invoicing, Kanban Boards, Meetings, Message Boards, Newsletter, Presentations, QR Codes, Spreadsheets, To-dos, Time Tracking, Video Chat, Store, Supporters, Website Builder and Password Vault from each feature's current product and Help. The pages describe what each feature does, its limits and how it connects to other Magpie features, and their product screenshots were captured again in light and dark, desktop and phone.