py: Move stack_ctrl_init() to mp_init().

As stack checking is enabled by default, ports which don't call
stack_ctrl_init() are broken now (report RuntimeError on startup). Save
them trouble and just init stack control framework in interpreter init.
bare-arm: Enable link map file.

This port supposed to be demo of uPy minimality, so let people behold it in
details.
py: Allow to disable array module and bytearray type.

array.array and bytearray share big deal of code, so to get real savings,
both need to be disabled.
bare-arm: Disable array module and even bytearray type.

To squeeze few more hundreds of bytes.
bare-arm: Hint of setting MICROPY_ERROR_REPORTING to REPORTING_TERSE.

Commented out so far, as enabled leads to dozen more bytes used actually
(due to string pooling effects).