Make asymmetric JWTs as default

[samarpan-b]

Is your feature request related to a problem? Please describe. Asymmetric JWTs are not used by default. The authentication service contains configuration parameters for both asymmetric and symmetric, but all of the other services reference symmetric signing in the docs. None of the examples use asymmetric signing.

Describe the solution you'd like Lets make asymmetric JWT as default in auth service, core package and all the other services with an option to go back to symmetric one for backward compatibility

Describe alternatives you've considered None.

Additional context None