Improve Java Module system (JPMS) support by Scala module

[cowtowncoder]

So, as part of Jackson 3.0 work, I have converted most modules to use module-info.java as part of build: formerly most modules used Moditect plug-in to just inject lightly processed variant into jar.
This work is under JSTEP-11 (https://github.com/FasterXML/jackson-future-ideas/wiki/JSTEP-11).

It looks like Scala module isn't using Moditect, and perhaps isn't even defining Automatic-Module-Name to define Module name. Given this, it is probably too big a leap to jump to creating and using module-info.java.

But it would nice to improve module metadata in some way: even if just adding Automatic-Module-Name.
This could be done both for 2.19 and 3.0 (master).

[pjfanning]

closing in favour of #569

JPMS has not really been embraced by the Scala community as far as I can see. Very little discussion of it.

[cowtowncoder]

Ok but would it at least be possible to add Automatic-Module-Name -- it's just an entry in MANIFEST.MF and provides minimal level?
(see f.ex https://stackoverflow.com/questions/46741907/what-is-an-automatic-module ):

"if the JAR defines the Automatic-Module-Name header in its manifest, it defines the module's name"

I don't expect actual module-info.java if situation really is such that Scala community cares little about JPMS (which I can understand, my own view of JPMS is pretty skeptical).
But automatic module name helps slightly with stability.

For 2.x it'd be I think com.fasterxml.jackson.module.scala and for 3.x tools.jackson.module.scala.