Add p2 update sites of eclipse to products

[PhilMFischer]

All Virtual Satellite product should contain the following update sites:

• https://download.eclipse.org/releases/2024-03/
• https://download.eclipse.org/eclipse/updates/4.31/

or the corresponding p2 sites fitting to the baseline eclipse of virtual satellite.

Should maybe be integrated into the build process, since the p2 sites are also used for building a product using maven/tycho.

⚠️ The ticket should be forwarded to IDE as well as CEF once this is finished!