Add icons to Add Data list and tutorial view

[alexfrancoeur]

Design has added icons for mysql, nginx and apache. I believe we already need more for Redis (logo), Docker (logo) and Kubernetes (logo) as they were last minute additions to 6.2.

We'll need to add these icons (and some new ones) to the Add Data list and tutorial view

cc: @nreese @tsg @formgeist @snide

[formgeist]

@alexfrancoeur I've created a PR for Eui to add the logos elastic/eui#341 cc @snide

[alexfrancoeur]

Awesome, thanks for the quick turnaround @formgeist!

[alexfrancoeur]

Re-opening because we still need to add these to the UI 😄