Move registry to interp and add support for functions and filesystems.
This will be used later for allow formats to add own functions and fq code.
Add gojqextra function helpers to have more comfortable API to add functions.
Takes care of argument type casting and JQValue:s and some more things.
Refactor interp package to use new function helper and registry. Probably
fixes a bunch of JQValue bugs and other type errors.
Refactor out some mpeg nal things to mpeg format.
Refactor interp jq code into display.q and init.jq.
Remove undocumented aes_ctr funciton, was a test. Hopefully will add more crypto things laster.
Padding could end up double.
Remove to*range($pad) as it probably just confusing to be able
to pad an existing range, what to show in hexdump etc? zero bits
that do not actuall exist at that range?
Add tests and binary stdout support to tests
Add explode for binary that explode into an array of the binary unit tobits
Remove scan_toend as it feels a bit weird and one can use tobytes | .[match(...):] instead
Some general cleanup also
Rename buffer to binary. Still some work left what to call buffer/binary in decode code.
Document decode value and binary type
Fix proper unit padding for tobytes and add still undocumenated extra padding argument.
Add some additional binary tests
