cpu/stm32*/ldscripts: remove all stm32 family linker scripts

cpu/stm32f0/ldscripts/stm32f030r8.ld

cpu/stm32f0/ldscripts/stm32f031k6.ld

cpu/stm32f0/ldscripts/stm32f042k6.ld

cpu/stm32f0/ldscripts/stm32f051r8.ld

cpu/stm32f0/ldscripts/stm32f070rb.ld

cpu/stm32f0/ldscripts/stm32f072rb.ld

cpu/stm32f0/ldscripts/stm32f091rc.ld

cpu/stm32f1/ldscripts/stm32f103c8.ld

cpu/stm32f1/ldscripts/stm32f103c8_bluepill.ld

cpu/stm32f1/ldscripts/stm32f103cb.ld

cpu/stm32f1/ldscripts/stm32f103cb_opencm904.ld

cpu/stm32f1/ldscripts/stm32f103cb_sparkcore.ld

cpu/stm32f1/ldscripts/stm32f103rb.ld

cpu/stm32f1/ldscripts/stm32f103re.ld

cpu/stm32f2/ldscripts/stm32f205rg.ld

cpu/stm32f2/ldscripts/stm32f207zg.ld

cpu/stm32f2/ldscripts/stm32f215rg.ld

cpu/stm32f2/ldscripts/stm32f215ve.ld

cpu/stm32f2/ldscripts/stm32f215vg.ld

cpu/stm32f2/ldscripts/stm32f217zg.ld