Revert "Update "Link to Bone" action"

This reverts commit fa970d93ee3902d9a8474fe03d455b690bc36889.

Conflicts:
	synfig-studio/src/synfigapp/actions/valuedescbonelink.cpp
Revert "Fix ValueNode_BoneLink"

This reverts commit 0861550372405fa8923ae117defd2c51be953f94.

Conflicts:
	synfig-core/src/synfig/valuenode_bonelink.cpp
Revert "Add list of bones into ValueNode_BoneLink"

This reverts commit e3dfa7c35c8f4506c85677a1f28dd050e982a7de.

Conflicts:
	synfig-core/src/synfig/valuenode_bonelink.cpp
	synfig-core/src/synfig/valuenode_bonelink.h
Draft of ValueNode_Bone::have_influence_on()
Draft of Action::ValueDescSkeletonLink
Implementation of Link to skeleton (Bugs!)