Custom Crypto Module

[williamposey]

Add support for a custom crypto module, in order for the SMaCS team to interface cryptolib with the Matchbox crypto IP

Known updates required:

• add function definition CryptographyInterface get_cryptography_interface_custom(void); to include/cryptography_interface.h
• create custom_stub/cryptography_interface_custom_stub.template.c under src/crypto
• add CRYPTOGRAPHY_TYPE_CUSTOM to the CryptographyType enum in include/crypto_config_structs.h
• add CMake logic to support a custom crypto interface
• add logic to the Crypto_Init() function in src/core/crypto_config.c to support the custom cryptography interface