Add more default tools running in CI?

[bnjbvr]

We could add a few useful tools in our opensource template, so as to not add them every single time:

• cargo-deny is nice to avoid multiple copies of the same dependency, or at least be aware of those (and also double-checking our license constraints),
• cargo-machete or cargo-udeps might be cool to remove unused dependencies,
• integrating with cargo-vet by default would be very sweet, but that's probably higher effort, so not sure it should be in the default case.

One could argue it's easy to remove extra tools, than it is to add them with a good default configuration. So I'd be in favor of having more tools by default, and after a fork of this repo template one can remove them on a case by case basis.