Add a README.md to the rust subdirectory as a guideline for writing
s390-tools tools in Rust. This includes build integration, dependency
handling, and a few coding style hints. Rust related information
is also added to the main README.md.
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
[hoeppner@linux.ibm.com: Adapt details in README.md]
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
