A basic integration of the prism library.
I tried to use our current library but it seems that the build is broken:
https://github.com/syntaxhighlighter/syntaxhighlighter/issues/428
So, instead, I switched to PRISM which seems to be more popular nowadays.
This module basically just adds the prism.js and the prims.css on our page, so we can just use it directly using this syntax:
<pre>
<code class="lang-php">
</code>
</pre>