py: Add portable framework to query/check C stack usage.

Such mechanism is important to get stable Python functioning, because Python
function calling is handled with C stack. The idea is to sprinkle
STACK_CHECK() calls in places where there can be C recursion.

TODO: Add more STACK_CHECK()'s.
stmhal: Use stackctrl framework.
tests: Add test for catching infinite function recursion.

Put into misc/ to not complicate life for builds with check disabled.