Responsiveness issue in Contribute page

[faucomte97]

Describe the bug
The "Our products" section of the Contribute page does not follow the expected layout when in mobile view.

To Reproduce
Steps to reproduce the behaviour:

1. Go to the Contribute page.
2. Through dev tools, view the page at a mobile size.
3. Scroll down to "Our products".
4. Observe that the image is still to the right of the text.

Expected behaviour
The layout should actually be: image on top of the text, then text under the image (like the following section).

Screenshots

Broken layout

An example of what the layout should be

Desktop (please complete the following information):
All

Good Places to Start
Template for that page: https://github.com/ocadotechnology/codeforlife-portal/blob/master/portal/templates/portal/contribute.html