Previous versions used a bundled version of the axTLS library. The
MicroPython project maintains their own fork[1], as development of the
library appears to have stopped (the last release was version 2.1.5 in
2019[2]).

This replaces the use of axTLS with two variants, one using mbedTLS and
one with no TLS support (and no upip, as it uses the ussl module). The
external mbedTLS patch (040-extmod-use-external-mbedtls.patch) comes
from Debian[3].

This also sets myself as the maintainer.

[1]: https://github.com/micropython/axtls
[2]: https://sourceforge.net/projects/axtls/files/
[3]: https://salsa.debian.org/yangfl-guest/micropython/-/blob/master/debian/patches/0006-extmod-Use-system-mbedtls.patch

Signed-off-by: Jeffery To <jeffery.to@gmail.com>