Added Callouts

[seankross]

I've grown to like Notion Callouts and GitHub Alerts and I would like to use them in the sciwiki articles I am drafting. The following code within articles produced the styling attached:

{% capture body %}
Here is a *point* of **information**.
{% endcapture %}
{% include callout.html type="info" icon="🔎" title="Info" content=body %}

{% capture body %}
Find a tip [here]().
{% endcapture %}
{% include callout.html type="tip" icon="💡" title="Tip" content=body %}

{% capture body %}
### The computer broke! 

Maybe don't do that next time. Instead you could:

- Ride a bike
- Go for a walk
- Sing in the shower
{% endcapture %}
{% include callout.html type="error" icon="⛔️" title="Error" content=body %}

{% capture body %}
Here be dragons.
{% endcapture %}
{% include callout.html type="warn" icon="🐉" title="Warn" content=body %}

{% capture body %}
With great power comes great responsibility.
{% endcapture %}
{% include callout.html type="quote" icon="🕷️" title="Quote" content=body %}

[seankross]

Realizing that {: .notice--warning} and {: .notice--info} are lighter-weight versions of this that are already implemented, but these stand out more visually.

[atombaby]

The minimal-mistakes CSS provides a way for us to customize these {notice} style callouts.