Feature request: Allow recipe pipeline to work on 'JSON' data instead of strings

**Is your feature request related to a problem? Please describe.**
While CyberChef is a very powerful tool, operations are working on strings. For certain problems that requires trying to interpret the string, for instance with regular expressions (Subsection).

An example use case I had, was that I needed to base64 decode part of a URI query parameter, using split to split the value.

**Describe the solution you'd like**
It would be very powerful if certain operations can optionally work on structured data. In the title I've mentioned 'JSON', altough that is more intended as a processing model than literal JSON.

For instance, ParseURL could have an option to return structured data instead of a string. Subsection could than select its target based on a JSON path instead of a regular expression.

All this would probably require operations to have a bit more meta-data and configuration to specify if they can accept strings and/or structured data and if they can produce string and/or structured data. I do think this would make CyberChef even more powerful.

**Additional context**
With the above changes, the following issues would probably be easily solvable:
https://github.com/gchq/CyberChef/issues/1820
https://github.com/gchq/CyberChef/issues/1756

The issue names no files, tests, or entry points. Start by mapping how recipe operations declare and pass their inputs and outputs, then assess structured-data handling, ParseURL results, and JSON-path selection. Done would require a defined, tested design for compatible operations and conversions.

Written by the indexing model from the issue text.