Talk page improvements

Tweaked a few things in the talk page and added a few new features:
- Removed h1/h2 override that could trigger issues with bootstrap and also made h3 larger then h2
- Changed regular design of the talk title and information
- Added slides link along with date and language
Merge branch 'slides-link' of github.com:rdohms/joindin-web2 into pr133
Merge branch 'pr133'