Replace testimonial icons with SVG versions

[sdepold]

[binlabs]

@sdepold Unfortunately, I've only been able to find SVG logos with wordmarks for Bitovi, Uphold, and Walmart Labs. We may need to reach out to the others and see if they'd be willing to provide them. But, hopefully this is a good start. Here are those three:

Bitovi	Uphold	Walmart Labs

I found an SVG logo for ErmesHotels, but it's just the logo icon itself - it doesn't include their wordmark. Here is that SVG in case it is any help.

ErmesHotel

For the record, that leaves Secure Coders and Snaplytics as the two that are missing completely. Plus ErmesHotels if the one above isn't good enough since it doesn't contain their wordmark.

[ephys]

Thanks! Even if it's not all of them that's already great :)