move the start mode variable to DebuggerStartParameters

By only providing a qtInstallDir variant

This splits up the edit and active settings. Let people try it and
report usability problems. I'm not 100% convinced of the layout either.

Cause that's the relevant context.

Based on a change by Denis Dzyubenko, done with mae.

remove DebuggerRunControl from DebuggerManager
use typedef for QSharedPointer<DebuggerStartParameters>

merge DebuggerRunControl::m_dumperLibrary{,Location} into StartParameters

has changes to make these files compile in Creator when Qt is compiled
in a namespace.

This conforms to the entry in the menu entry, wich already changes its
name accordingly to comply with the Apple HIG.

Also, adjusted the docs that were missing the change of location in the menu.

It's merged now into debugger/gdb and the "runner" is a new standalone wrapper