Related to #7982, this PR refactors the code
such that we validate the OPA or JWKS in a
common place.
This is also a refactor which is already done
in the new config migration change. Attempt
to avoid any network I/O during Unmarshal of
JSON from disk, instead do it later when
updating the in-memory data structure.
This PR introduces two new features
- AWS STS compatible STS API named AssumeRoleWithClientGrants
```
POST /?Action=AssumeRoleWithClientGrants&Token=<jwt>
```
This API endpoint returns temporary access credentials, access
tokens signature types supported by this API
- RSA keys
- ECDSA keys
Fetches the required public key from the JWKS endpoints, provides
them as rsa or ecdsa public keys.
- External policy engine support, in this case OPA policy engine
- Credentials are stored on disks
Harshavardhana