Add EuiIconTip

[cjcenizal]

We can use them to replace the kbn-info directive in Kibana. This is something we need to do before 6.3 because a recent change broke these tooltips:

[snide]

Looks good. Do you mind adding to the docs that it accepts / passes down the props to EuiToolTip? Maybe show that in the example... add position="right" to one of them or something.

Might wanna name it EuiIconToolTip just because it's directly related, but I don't care strongly about it if we wanna go with the shorthand.

[cjcenizal]

Thanks @snide, good point about the docs. I like the short-hand so I'm going to leave the name as-is.