Changes for the 5.0.0-beta2 pages (rebased onto dev_4_4)



This is the same as gh-29 but rebased onto dev_4_4.

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This PR 

- backports some changes from #12 (in 5.0.0-beta1) tag to handle new 5.0-specific JARs in BF downloads page
- fix non initialized variable when tag is only present on the snoopycrimecop remote
- remove hard-coded versions from `omero_downloads.html`