JBIDE-11065: Use only mojo

* added p2StatsUrl
* remove uncategorized
* added READMEs to output repository

* fetch-zips-for-aggregate goal on site and soa-site

* Output copied into a site_assembly.zip for publish
JBIDE-11065: Use gstring-maven-plugin to generate result page
JBIDE-13065

* Re-added fetch-zips
* Improved links in results
* results only on-demand with -Presults