[QA] salt is replaced by cumin

[Antoine Musso]

Hello,

On deployment-prep and integration, I have removed Salt entirely in
favor of Cumin.

It is mostly similar but way better to keep the inventory, make sure you
reach all the instances.  Cumin comes with an elaborate query scheme.

One requires sudo access to be able to use it since commands are
executed on instances as the root user.

Instances:

- deployment-cumin.deployment-prep.eqiad.wmflabs
- integration-cumin.integration.eqiad.wmflabs

Examples:

 sudo cumin '*' 'true'
 sudo cumin 'name:deployment-mediawiki' 'true'

The documentation is quite nice, you certainly want to read the part
about selecting hosts:

https://wikitech.wikimedia.org/wiki/Cumin


-- 
Antoine "hashar" Musso