Jackson 3.0, JSTEP-9: deprecation and removal of jackson-module-jsonSchema module(s)

[cowtowncoder]

As per more general JSTEP-9 -- deprecation and removal of some Jackson 2.x modules from 3.0 -- the current plan is for JSON generator component to be discontinued, not upgraded or maintained for Jackson 3.0.
This is strictly based on years-long lack of active Maintainer for the module, and outdated implementation (JSON Schema v3 only)

If an active maintainer was found, we could change the plan.

This Discussion is created to re-check interest in having these modules available for Jackson 3.x, based on a user reaching out.

NOTE: "removal from 3.0" simply means no migration to build 3.x versions -- not deletion of code or repo or anything like that. Modules will be supported for 2.x regardless.

[cowtowncoder]

/cc @pjfanning @JooHyukKim @sdeleuze @reda-alaoui