Improve graph node labels - remove parentheses

[jshaughn]

To add necessary discriminators to Graph node labels we append namespace and/or cluster names in parentheses. This has proven to be confusing and can also be hard to read. It originated before we used PF badges and can now be improved by using fully-badged information.

This is related to #5922, which suggests that we add back single-node parent-boxes. But that approach has proven to be cumbersome for larger graphs. Hopefully this will be sufficient. If not, we could add single-node boxing back, as a configurable ui-option (but I don't really want to).

Before:

After:
TBD