Non square developers logos are cropped

[loicteixeira]

Developers logos currently use the fill-80x80-c100 rule which crops non-square logos.

Using max-80x80 doesn't crop it but doesn't look great either (althougth might be a good first quick fix).

We might need to write a custom filter which does the same as max-80x80 but also centers the image horizontally and vertically. Custom filters aren't documented but we can look at the implementation of the built-in filters and how to register them.

We might also want to look at #94 at the same time.

[loicteixeira]

☝️ The PR above implement the quick max-80x80 fix but leaving the issue open as it will require more work to look good.

[haydngreatnews]

Would it be easier to fix the vertical alignment of the logo in CSS?

max-80x80 would give an image that was (for example) 80 wide, and 20 high, and if the vertical alignment could be adjusted, it would save writing a whole new filter