POM: remove distribution management

The preferred way to deploy to the ImageJ Maven repository is via the
deploy-to-imagej profile.
Collapse multimodule project into a single module

We will only ever have one SCIFIO OME-XML library. Any other modules
(e.g., the scifio-omero library) would go into their own repositories.
POM: rename artifact to scifio-ome-xml
POM: tweak project description
POM: fix CI URL
POM: remove SciJava mailing list

As a rule of thumb, the SciJava mailing list is for discussion of code
in the scijava namespace. The SCIFIO mailing list should be preferred
for discussion of SCIFIO modules including scifio-ome-xml.
mailmap: fix Mark Hiner aggregation
POM: fix hinerm email address