Sponsors design changes

[grappler]

• [x] 1. The micro sponsors design on the Sponsors page needs to adapted.

• [x] 2. Could we make the sponsor logos on the front page about the same height?

• [x] 3. As we have only three Gold sponsors could we centre the third sponsor?

[grappler]

I am not sure if we can do something about the mixed matched background colours of the logos.

[ocean90]

You could make the background of the sponsors section white.

.wcorg-sponsors {
    background: #fff;
    box-shadow: -600px 0 0 0 #fff, 600px 0 0 0 #fff; /* left/right overflow */
}