Clean up contributors.md

[deissnerk]

As decided in the weekly call, I removed the company names and put the names in alphabetical order.

[duglin]

LGTM thanks!

[deissnerk]

I removed the empty lines at the end. Yes, there were a few names without links. I did not try to add links to avoid confusion. If somebody provides the correct github links, I will add them.

[deissnerk]

Thanks for bringing this whole issue to my attention @devguyio ! 😄

[jskeet]

Yes, there were a few names without links. I did not try to add links to avoid confusion.

I think that's reasonable. I guess if folks want to be linked, they can create their own PRs :)

[duglin]

Approved on the 7/18 call