Remove experimental label from dominant color module and turn on by default for new installs

[spacedmonkey]

Feature Description

Enable dominant color module by default and remove experiemently flag.

[spacedmonkey]

Thoughts on this one @pbearne @felixarntz

[pbearne]

yes I feel we should do this

[felixarntz]

@spacedmonkey @pbearne I agree with the additional polishing this has been getting we should be good making this non-experimental. Let's make sure to look out for additional feedback. It would be great if we could ship this as non-experimental in the upcoming 1.3.0 release and shortly after publish the feature proposal post for WordPress core.

[mxbclang]

@felixarntz Just to clarify, is the plan for 1.3.0 to remove the experimental flag and enable the module by default? I'd like to update the issue title if we're only doing the former.