Replace tika-files.zip by a tika-files dir

[dadoonet]

We are maintaining a ZIP file which contains a subset of tika project test files.

https://github.com/elastic/elasticsearch/blob/master/plugins/ingest-attachment/src/test/resources/org/elasticsearch/ingest/attachment/test/tika-files.zip

It would be easier for debugging/testing to have actually a directory which contains all those files. Adding or replacing the content would be then much more easy.

Also having a flat dir would may be help us to compare or "synchronize" more easily with Tika project files.

Thoughts?

[dadoonet]

Discussed in fix it friday. We want to do it.
May be try to compress individual files one by one to see if can reduce needed space.