Fix BLESS plugin installation as additional OSATE component

[lwrage]

Installing the BLESS plugins via the additional components dialog does not work, so the option should be removed. It looks like the BLESS p2 repository is configured in a way that blocks installation via the dialog.

[lwrage]

It turns out that BLESS is now available as a proper p2 repository at a different URL. Installation via that URL works.

URL is updated and BLESS can now be installed as an additional component.