New helper nodeName to allow centralized formatting of hostnames

[mruettgers]

This PR adds a new helper "nodeName" to allow a centralized handling of extra long or empty hostnames.
Long node names will be trimmed to avoid layout issues, empty node names will be replaced with the node id in square brackets.

[jplitza]

Shouldn't this be the Unicode character "…" instead of three single "."?

[jplitza]

I support the idea, both content-wise (shortening node names) and implementation-wise (introducing a single helper function that does the job). However, my knowledge of the codebase is too scarce to decide whether the implementation is done properly.

[tcatm]

I wouldn't call it "trim". That usually implies cutting excess whitespace from strings. "shorten" might be better suited.

I'd also create two functions, e.g. shortenNodename and prettyNodename and chain them when a shorter name is required (e.g shortenNodename(prettyNodename(d))).

[tcatm]

Actually, call it truncate as we don't actually do any magic to retain a meaningful hostname. Also, use "…" instead of "...".

[tcatm]

Also make sure, that truncateNodename("𝟘𝟙𝟚𝟛𝟜𝟝𝟞𝟟𝟠𝟡", 3) + "foo" actually returns "𝟘𝟙𝟚foo" and not just "𝟘𝟙" with some garbage at the end.

[tcatm]

On the other hand, why don't we use CSS?

Set this on a table cell:

text-overflow: ellipse;
overflow: hidden;
white-space: nowrap;
max-width: 0;

[mruettgers]

I like the CSS based solution for truncating.
But this does not solve issues caused by missing hostnames wherever they are expected to be available as string objects.
So we need both, the CSS based solution and a central function for formatting the node name.
I'll have a look on this later.