Major re-design of the thread list pages.

This is a major-change of how the thread list page is rendered. This has been long-time broken with various reported issues. This aims to remove a bunch of different classes used in responsive design.

Here is a brief summary of the visual changes:

• Reduce the margin on left and right side from 15px (added on multiple levels of columns since they are applied on all col-XX classes. This is defined by the grid-gutter-width variable.
• Remove the margin-top in the thread-date.
• Put the list address in the same line as the name in Hyperkitty's index page.
• Make participants and number of replies as badges.

Some screenshots from Laptop sized view:

Mobile views:

Index page in mobile