Add CryptoInterface library (#6961)

* - Add CryptoInterface library.

- Add TypeConversion core files.

* Fix compiler errors.

- Make HelloCrypto.ino stylish.

- Include assert.h in CryptoInterface.cpp.

* - Move base36 arrays to PROGMEM in TypeConversionFunctions.cpp.

- Add deprecated attribute to SHA1 and MD5 hashes.

- Remove _warningsEnabled since this has been replaced by the deprecated attribute.

- Prefix all getters with "get".

- Move all CryptoInterface functionality to the experimental namespace.

- Change formatting of core files.

- Improve comments.

* - Update keywords.txt.

* - Remove WiFi.disconnect() from setup() in HelloCrypto example since it no longer seems to be required.

* - Classify everything.

- Remove delay in setup() from HelloCrypto example since it does not seem to be required to prevent missing initial Serial prints.

- Mark type conversion functions as big endian.

- Update keywords.txt.

* - Remove namespace experimental.

- Create ESP.random functions in the core based on the defaultNonceGenerator code, and use these in defaultNonceGenerator.

- Rename CryptoInterface to esp8266::Crypto and move all functionality to the core.

- Remove need to #include <bearssl/bearssl.h> in the Crypto header file by changing br_hkdf_context to ::br_hkdf_context.

- Restyle code files for core usage.

* - Re-add namespace experimental.

- Improve comments.

* - Remove namespace esp8266.

- Rename namespace Crypto to namespace crypto.

Co-authored-by: Anders <andlo151@student.liu.se>
Co-authored-by: Develo <deveyes@gmail.com>

libraries/esp8266/library.properties

@@ -1,6 +1,6 @@
 name=ESP8266
 version=1.0
-author=Simon Peter,Markus Sattler,Ivan Grokhotkov
+author=Anders Löfgren,Simon Peter,Markus Sattler,Ivan Grokhotkov
 maintainer=Ivan Grokhtkov <ivan@esp8266.com>
 sentence=ESP8266 sketches examples
 paragraph=