update launcher name and layout upgrade path

[martinlippert]

For the 5.0.0 release, we will ask users to start with a fresh installation and we should probably disable any automatic upgrade paths.

This will include changing the launcher name for the Eclipse-based distribution and maybe change the branding feature IDs as well - but that has to be discussed.

I also tend to switch the version of the language server piece to the same than the major Spring Tools version to have the same version across the place - which also remains to be discussed.