Add ability to tag/group services for filtered service view

[gpickin]

We love portainer, and we are running a lot of services, and that services list is getting a little hard to maintain.

If we could group them, into clienta, clientb, internal, webserver, db etc it would be nice to be able to filter the service list by those groups.

Maybe having tags, for cross filtering might be nice.

[deviantony]

Docker comes with label support, we might be able to leverage these and allow the user to filter by labels when searching in the services list view. What do you think @gpickin

[gpickin]

I think leveraging that would be easiest... and make the most sense.
A select2 type filter would be nice. Not sure if there is enough real estate to show the labels in the list view.