Changes include:
- Some mbedtls source files renamed or deprecated.
- Our `mbedtls_config.h` files are renamed to `mbedtls_config_port.h`, so
they don't clash with mbedtls's new default configuration file named
`mbedtls_config.h`.
- MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE is deprecated.
- MBEDTLS_HAVE_TIME now requires an `mbedtls_ms_time` function to be
defined but it's only used for TLSv1.3 (currently not enabled in
MicroPython so there is a lazy implementation, i.e. seconds * 1000).
- `tests/multi_net/ssl_data.py` is removed (due to deprecation of
MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE), there are the existing
`ssl_cert_rsa.py` and `sslcontext_server_client.py` tests which do very
similar, simple SSL data transfer.
- Tests now use an EC key by default (they are smaller and faster), and the
RSA key has been regenerated due to the old PKCS encoding used by openssl
rsa command, see
https://stackoverflow.com/questions/40822328/openssl-rsa-key-pem-and-der-conversion-does-not-match
(and `tests/README.md` has been updated accordingly).
Signed-off-by: Carlos Gil <carlosgilglez@gmail.com>