psa: Refactor psa_destroy_key()
psa: Refactor psa_destroy_key()

Create a new function psa_remove_key_from_memory() from psa_destroy_key().
This is needed as psa_destroy_key() will remove all key data, including
persistent storage. mbedtls_psa_crypto_free() will now only free in-memory
data and not persistent data.

NXPmicro/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls