Since JDK 1.0 the SequenceInputStream provides the ability to read multiple InputStreams in sequence in a way transparent to the calling application.

The Implementation of SequenceInputStream was done in a suboptimal way, and since the behavior was not clearly specified in the JavaDocs, optimizing the implementation could break existing applications as the non-specified but de-facto behavior might change.

To allow further optimization of input stream sequences (like higher performance, easier maintenance, easier usage, ertc.), one solution could be to keep SIS as-is, but provide another way to deal with input sequences in new or revised applications.

One first step towards this goal is the exploration how such an API should look like, providing a demonstrator to learn about the pros and contras of implementation approaches. This PR has the target to provide a demonstrator for such a new input stream sequences API.

In particular, the code provided by this PR will...
* ...hide all implementation specifics, in particular the exact class name of the produced class, behind a shading factory method, to allow future changes in any direction.
* ...not be synchronized nor otherwise prepared for any concurrent access other than creating a new class instance.
* ...initially provide multiple concurrent API approaches / proposals, which may get sorted in the further discussion of this PR. This means, it is open whether the result will be one of those proposals, all of them, or none at all.
* ...be optimized for best performance as one top target.
* ...possible not cover all use cases of SIS but only the most common ones.