Use one JWT library

Keeping with Minimize Dependencies, we exclusively use github.com/lestrrat-go/jwx/v3 for all JWT operations.

Pros

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• This library is focused, mature, and well-maintained.
• This library appears to have the capabilities that we need.

Cons

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• This can require additional work to refactor code to use preferred dependencies.
• Support for secp256k1 currently requires a build flag.
• New key types might not be supported.

Comments

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