Make crypto provider configurable

[dulanjal]

Description:
Currently, BouncyCastle ("BC") crypto provider is hardcoded in org.wso2.carbon.core.util.CryptoUtil (E.g. Refer [1]), which is used for conducting internal encryption tasks such as OAuth2 token encryption. We should check the feasibility of making this configurable in order to allow use of FIPS 140-2 compliant crypto providers (E.g. "BCFIPS").

[1]

carbon-kernel/core/org.wso2.carbon.core/src/main/java/org/wso2/carbon/core/util/CryptoUtil.java

Line 153 in 9e8dab2

encryptedKey = cryptoService.encrypt(plainTextBytes, algorithm, CRYPTO_API_PROVIDER_BC);