Polishing Tassel

[Aki-108]

• [x] Add a toast that tells the user where to open Tassel
• [x] Display extensions in a grid, if the screen is wide enough
• [x] Test in different Browsers
• [x] Remove console.log from extensions
• [x] Allow buttons in toasts
• [x] Only update the Toasts-Read timestamp if it's newer than the saved one
• [x] Add discriptions to settings
• [x] Clean up code
• [x] Comment code
• [x] Toast links underlined
• [x] Allow Tassel links in Post body
• [x] Shorten Sidebar better