Add socialToolbar component

Doesn't allow any configuration, i feel like we open stuff up too much to config and there's no need yet.

Uses some funky line breaking indenting in places, not normal.

Has a looping spec which may or may not help matters. Removes duplication but makes debugging more awkward. I'm indifferent.

Feel free to push back on any of the above if needs be. Definitely feel free to improve my regex where possible. I feel like maybe i should be making use of the $1 stuff to reduce duplication of the separator but not sure if that's true or if you can in that case.

Feeling antisocial after all this.
I could be missing something, but I'm not sure passing in `this.getUrl()` is necessary here... it could seemingly just be called from within `_updateLinks` below.