The reasons to make this switch are:
- The axtls library is not being maintained/updated, mbedtls is.
- So CI and tests can run against mbedtls, which is now the main TLS
library used by the ports (eg stm32, rp2, mimxrt, esp32). Only esp8266
uses axtls.
Increases unix standard build on x86-64 by about 89000 bytes.
Signed-off-by: Damien George <damien@micropython.org>
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.