regtools/qeditor: rewrite soc handling

The code was a mess with respect to soc handling: some code just plain copied
the SoC descriptor which are big objects, some was using indexes. The new soc
factor out everything in a few classes which hide these ugly details so that
descriptors are never copied.

Change-Id: I17af8b47f997a528b58221621389d42d24fded93
8 files changed