[issue172] Migrate to a Jakarta namespaced activation API.

[jamezp]

Resolves #175

I'm happy to back port this to 2.13 if that is acceptable as well.

[cowtowncoder]

Yes, given that 2.13.3 probably simply does not work, I think rebasing this against 2.13 would make sense. Not sure if 2.13.4 will be released before 2.14.0 but just in case.

One quick procedural thing: I think I may need a CLA from you; it's here:

https://github.com/FasterXML/jackson/blob/master/contributor-agreement.pdf

and the usual way is to print, fill & sign, scan/photo, email to info at fasterxml dot com.

However: we also do have a Corporate CLA (CCLA) by Red Hat corporation from October 2017.
So if you work for Red Hat, contribution could be under CCLA too. Just let me know if that is ok; I am fine either way (less paperwork if CCLA works given it's already stored). :)

[jamezp]

@cowtowncoder Perfect. I'll create a 2.13 PR as well.

I do work for Red Hat and I'm happy to use the CLA for the contribution.

[cowtowncoder]

Great! So, only 2.13 PR really needed; I can merge forward from there.

I hope to check this later today/tonight; change is fine but update release notes etc.