Update labels on ScaleSet and Runners

[pauloconnor]

This should address #4424 and #4425

[nikola-jokic]

I'm not sure if strings.Join on labels is the right thing to do to set the labels, because the combination of labels joined with "," must have less than 64 characters.

Valid label value:
must be 63 characters or less (can be empty),
unless empty, must begin and end with an alphanumeric character ([a-z0-9A-Z]),
could contain dashes (-), underscores (_), dots (.), and alphanumerics between.

We can set the annotation on these resources, because it doesn't have such restrictions as far as I can tell.