Add SHA512 token fallback for OAuth application secrets

What does this MR do and why?

We are introducing SHA512 hashing for oauth application secrets which is faster and compliance with FIPS. This commit adds fallback mechanism so that actual hashing change can be rolled out safely

This MR also consolidate OAuth token and OAuth application hashing mechanisms together.

References

• Related to #551169 (closed)
• Similar MR for Oauth access token: !198910 (merged)

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