stm32l: split l0/l1 support no jtag, different HSI settings

L0 is cortex m0+, so different id codes, SWD only, different addresses
for the clock speedup.  It has no endian options, no boundary scan.

Removed all L0 specific portions from L1 files, and renamed files to clarify
their purpose.  The deprecated stm32lx_stlink.cfg is kept as is, as it is only
around for backwards compatibility with prior releases.

Tested on STM32L053 Discovery and STM32L151 Discovery.

Has _not_ been tested with jtag on L1.

Signed-off-by: Karl Palsson <karlp@tweak.net.au>