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.
Rename s/interface{}/any/g
Preparation for using generics in decode API and native jq funcations etc
Remove some unused linter ignores as linter has been fixed
Move scalar into own package.
Split scalar code into decode related scalar code (that reads etc) and
scalar code that just transform the scalar value.
Use a scalar.Mapper interface instead of just a function.
Make mappers, assert and validat impement the interface.
