Simplify start menu entries
* src/inst-sections.nsi: Remove old removal code. Remove Manual links. Install Kleopatra/GPA entries in top level. * src/installer-finish.nsi: Remove start menu entry removal. * src/installer.nsi: Remove start menu page.
We might want to add a custom installation option that will allow
to select startmenu again. But installing many start menu entries in
a subfolder is no longer state of the art for Windows.