Mainly useful for testing WiFiClientSecure in local environments.
If allowSelfSignedCerts is called before verifyCertChain, then the
certificate chain will be verified, but the final certificate may be
self-signed.
- update ssl_client_new signature
- add max fragment length negotiation support (hardcoded to 4096 bytes)
- build axtls with -f{function,data}-sections, ~1k less DRAM usage,
~3k less flash
- strip prefix from build paths in debug symbols
