check_token fails for endpoints without DOMAIN entry

[e-nouri]

check_token fails for endpoints without DOMAIN entry, this is for example the case if you set SCHEMA_ENDPOINT, on the root /schema it will always fail because this resource_conf = config.DOMAIN[resource] it is a pretty easy fix, I changed it to this resource_conf = config.DOMAIN.get(resource, {}) .

I fixed it on my own fork, but did not add unit tests, if you accept pr, i will make one to fix this. I am leaving this for reference here, because it seems like the repo is not being updated lately.
Cheers,