POM: add profile to generate aggregated javadoc
POM: add profile to generate aggregated javadoc

Thanks to Johannes Schindelin for blazing the trail there with Fiji:
https://github.com/fiji/fiji/commit/25d5510917a2d091d998f2489dc91edb3e6ec0c8

biovoxxel/imagej,biovoxxel/imagej,TehSAUCE/imagej,TehSAUCE/imagej,biovoxxel/imagej,TehSAUCE/imagej