Automatically Order Labels based on Annotation Frequency

**Is your feature request related to a problem? Please describe.**
I have been using Label Studio to annotate texts for classification tasks. When there is high label cardinality i.e. too many categories, it is frustrating to look for specific one among the list. I have later manually re-ordered the labels based on their frequency of use and it significantly improved my annotation speed.

**Describe the solution you'd like**
The labels on the annotation UI can be re-ordered periodically based on their respective frequencies. i.e. most used category will be at the beginning of the "list". So frequently used categories will be easy to find and under the hand for faster annotation.