feat(managers/custom): generic manager for json files

[RahulGautamSingh]

Changes

• Implement a new custom manager which uses jsonata queries to extract the deps info from a package file. Details are similar to regex manager implementation, except that we do not need to explicitly handle the recursive matching as that is already handled by the jsonata query language.
• Added tests
• Added docs

Context

• Json Part of: Generic manager that understands json and yaml structure. #15193
• Carrying forward work done by @dariocc in feat: Implement json-jsonata manager that can extract dependencies json configuration files #17077

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository https://github.com/Rahul-renovate-testing/repro-15193

[rarkins]

I definitely want to see an example of this working on a real repo

[RahulGautamSingh]

I definitely want to see an example of this working on a real repo

Test run on renovate repo, targeting the package.json and extracting dependencies, devDependencies, optionalDependencies
Rahul-renovate-testing#2