Parse roles from JWT payload

[jleach]

Some applications need to make sure only specific people can preform tasks rather than any authenticated user. This is done by assigning the user roles. This feature adds the ability for the ImplicitAuthManager to parse roles from the JWT.

[jleach]

@patricksimonian I created my tests outside of yours because they're a bit different. I wonder if we can adapt yours to use fixtures so there is code to write within each test. LMK what you think of the way I did it.

[patricksimonian]

@patricksimonian I created my tests outside of yours because they're a bit different. I wonder if we can adapt yours to use fixtures so there is less code to write within each test. LMK what you think of the way I did it.

Yeah I like it. I'll raise that as an issue

[jleach]

I'll do this now.