MH-13412, Deprecate PathSupport.concat(…)

[lkiesow]

Most of Opencast's PathSupport class are re-implementations of of
functionality built into Java's standard library and it would make much
more sense to use the standard library instead.

This patch deprecates a number of PathSupprt methods, describing the
alternatives from the standard library.

[gregorydlogan]

I'm 90% certain I was just advising @rute-santos to use these methods, sooo... I'll take this PR :-)

[lkiesow]

Happy to have a reviewer ;-)

I was just advising @rute-santos to use these methods

Any particular reason for using PathSupport over the built-ins? Pull request #755 contains an example for switching to the built-ins:

- File configFile = new File(PathSupport.concat(new String[] { uiConfigFolder, orgId, component, filename }));
+ File configFile = Paths.get(uiConfigFolder, orgId, component, filename).toFile();

Not only do I think that it is actually simpler to use but I'm also all for having less custom code.

[gregorydlogan]

Apologies, I was thinking of UrlSupport.concat, not PathSupport. I'm all for reducing custom code in favour of built-ins.