* cmake: Fix location of modprobe.d config.
* cmake: Use cmake variables for install locations.
This commit add the following two Cmake variables to
change the install location of the udev and modprobe
configuration files:
- STLINK_UDEV_RULES_DIR
- STLINK_MODPROBED_DIR
* doc/compiling.md: Add info about new CMAKE variables.
* debian: Use CMAKE variables for build.