feat(emoji): using at.js for emoji selection

I really needed some auto completion for emojis :smile:

Why at.js/caret.js and not angular-at-directive:
- at.js repo is newer and tested
- easier to add data than in at-directive
- with the at-directive every textarea would had to add an ul-List for each item

I could add my "at-emoji" directive to:
- Tag Creation / Edit
- New/edit habits/dailies/tasks/rewards 

The Tavern / Guild / Party Chats didn't work every time, so I removed them from this checkin.

So ... have fun using Emoji's easier than before :tongue: