Change blockquote style to pullquotes

[kimroen]

Fixes #21

This adds styles so that the default markdown blockquotes will be rendered as pull quotes.

All three of these styles will result in a pull quote:

>Jeg synes det er veldig sosialt å møte alle man leier direkte til.

<blockquote>
  Jeg synes det er veldig sosialt å møte alle man leier direkte til.
</blockquote>

<blockquote class="pullquote">
  Jeg synes det er veldig sosialt å møte alle man leier direkte til.
</blockquote>

These will look like this:

If you want to have the old style, you can add the class "blockquote", like this:

<blockquote class="blockquote">
  Jeg synes det er veldig sosialt å møte alle man leier direkte til.
</blockquote>

This will look like this:

@chreriksen If you have any feedback on this, now is a good time. If not, then I'll go through with this change tomorrow 👍

[kimroen]

I got some feedback that the pullquote text could be larger, so I have increased that to 1.3em (as opposed to the 1.15em it used to be). Also made a slight refactoring to avoid overriding styles.

We'll deploy this now to see how it works in practice.

[kimroen]

@chreriksen This change has been deployed now.