Messages should be specified at the Grommet level instead of the component level

[jcfilben]

Please describe what the rule should do:
If the messages prop is used at the individual component level, advise users to switch to using the messages prop at the Grommet level instead.
What category of rule is this? (place an "X" next to just one item)

[ ] Warns about a potential error (problem)
[x] Suggests an alternate way of doing something (suggestion)
[ ] Other (please specify:)

Provide 2-3 code examples that this rule will warn about:

<Button messages={...} />

Why should this rule be included in eslint-plugin-grommet?
In Grommet we want the general direction for messages to move away from specifying them at the component level and instead specify messages for the entire application at the Grommet wrapper level.