Move tika-server.jar to, say /tika-bin/ for Tika 2.x?

[tballison]

With the modularization of tika 2.x, it would be useful to allow users to drop extra jars in a /tika-bin/ directory for extra-functionality. For example, adding the tika-fetcher-http module might look like this: https://cwiki.apache.org/confluence/download/attachments/186877907/Dockerfile?version=1&modificationDate=1629216716183&api=v2

If we added the -cp /tika-bin/* stuff, though, users could extend logical spark more easily.

If there are better options, please let me know.

Thank you!