Bump to latest pom-scifio

Updated to pom-scifio 2.3.
OMEXMLFormat move translation

The Translation process for this format requires ImageMetadata, thus it
is incorrect to have it occur at the Metadata translation signature.
OMEMetadataService: add ImageMeta signatures

As this population process just requires ImageMetadata, it makes sense
to expose ImageMetadata-only signatures and not just Metadata.