refactor code and cleanup claims usage

[agaudreault]

Summary

RegisteredClaims and MapClaims are used in the code, and ArgoClaims is wrapping RegisteredClaims. How we access the claims then is either through interface methods, property access or with jwt helper functions to convert the values of MapClaims.

The current code is confusing, error prone and not necessary.

Motivation

• less serializations means faster code
• code is easier to understand
• less chance of error

Proposal

Use the ArgoClaims wrapper everywhere.

[sbin64]

/assign

sorry @agaudreault could you elaborate more on that? Which specific files do you want to get through?