Berry support for crypto.SHA256

[s-hadinger]

Description:

Add Berry support for SHA256. See documentation for examples. This will be needed for the Matter protocol. Size impact is minimal because SHA256 is already used in TLS.

Example test vectors from https://www.dlitz.net/crypto/shad256-test-vectors/

import crypto
h = crypto.SHA256()

# SHA256 of empty message
assert(h.out() == bytes("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"))

# (first 16 bytes of RC4 keystream where the key = 0)
h.update(bytes("de188941a3375d3a8a061e67576e926d"))
assert(h.out() == bytes("067c531269735ca7f541fdaca8f0dc76305d3cada140f89372a410fe5eff6e4d"))

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with Tasmota core ESP32 V.2.0.5
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass