Render JWT claims after successful login

[laurelnaiad]

This is intended to address #99 / Display JWT claims after successfully signing in.

I understand from the OP that there may be some concern about displaying the information.

For that reason, I've broken this into two commits, the first of which exposes the claims to the commandline template, and the second of which actually renders the claims in the template. If the security concern persists, and you don't want to render the claims by default, then perhaps the first commit could still be merged, so that folks who want to "throw caution to the wind" can do so via a custom template?

Also, I allowed a random trailing space in the template to be removed by my editor. Hope that's ok. :)

[laurelnaiad]

Here is an example of the output.

I allowed the default 6 digits of decimal precision for the floats. My understanding is that the spec does not forbid precision finer than one second, even though my provider, dex, doesn't use it.

[mleklund]

I would love to have this for nothing more then additional flexibility on what I can use in a custom template. Username's look like UUIDs in keycloak for example, so I could use Claim.name.