Restructure to split out extra filters and their dependencies

[jamesmudd]

jHDF now depends on compress-lzf and lz4-java to offer support for additional HDF5 filters. This is good when these filters are needed but it makes the base jHDF dependencies larger, for people who don't require these extra filters.

The ide would be to split out a separate gradle project jhdf-extra-filters that has these dependencies and the required filter impls and tests. It would produce a seperate jar artifact. When this extra jar is present on the classpath the extra filters would be available this service loading is already in place.

The benefit would be people who don't require the extra filters are not forced to take the dependencies.