Make minimal runtime uses own linux-minimal.bst

Part of #1523

Result: 74 MB

This MR contains two commits. One for copying the element elements/components/linux.bst to a new element elements/components/linux-minimal.bst, and the other to make the dependency inside the element elements/vm/minimal/deps.bst use the new created element.

The reason to create a new element is because that the linux source file is introduced by the element elements/components/linux.bst, which means modifying this element will also damage other build targets. The new element will now copy nothing to the minimal runtime's filesystem.