Custom ceritificate to verify server (TLS/HTTPS)

[MeowKatee]

Motivations

I cannot verify some servers even if I set CONFIG_MBEDTLS_CERTIFICATE_BUNDLE_DEFAULT_FULL=y, I need to pass cert_pem, which was impossible to pass to EspHttpConnection

• Would you like to implement this feature? y

Solution

Allow to pass cert_pem and set custom ceritificates

Alternatives

Make esp-idf-sys more configurable. Due to crates.io limitation, it could only access $OUT_DIR for esp-idf-sys, and no other crate could ever write certificate to its OUT_DIR. Therefore, specifying relative CONFIG_MBEDTLS_CUSTOM_CERTIFICATE_BUNDLE_PATH becomes meaningless. (This applies to #402, too, though espflash could take care of partitions, but it cannot handle CONFIG_MBEDTLS_CUSTOM_CERTIFICATE_BUNDLE_PATH.)

Additional context