All the downstream kernels reference ../../.shared-patches in their
symlinks. Now that we have moved device ports to device/testing/*,
those symlinks are no longer working.
Changing the path would require fixing all downstream packages *and*
a new pmbootstrap release. Overall it seems easier to move the
.shared-patches folder to device/.shared-patches.
Since it is only relevant for downstream kernel packages in device/
that might be a better place in general.
This introduces a new .shared-patches folder. New
"pmbootstrap aportgen" code will make use of this, and create symlinks
to the patches inside that folder when running
"pmbootstrap aportgen linux-..." (or using the new device wizard).
