ivory-bsp-stm32: remove stm32_init data-files, disable all drivers, build works
ivory-freertos-bindings: use Ivory.Artifact.Template

The HStringTemplate methods for transforming FreeRTOSConfig.h.template are
generally useful, so they have been moved to Ivory.Artifact.Template
tower-freertos-stm32: rename some files, use config from ivory-bsp-stm32
ivory-bsp-stm32: generalized vector table, moving towards a config system
tower-freertos-stm32-tests: simple-test uses config (still a little broken)
tower-freertos-stm32: delete unneeded support files, rename others
ivory-bsp-stm32: refactor init code

linker script moved to tower backend
ivory-bsp-stm32: move crystal clock config constructor to a general purpose function
ivory-freertos-bindings: we can safely leave croutine files out of the build.
tower-freertos-stm32: support file fixups
tower-freertos-stm32: proper linker script templating and init code gen
tower-freertos-stm32-example: fix build for new config