<!-- The PR description should answer 2 (maybe 3) important questions:
-->
### What
We'd like to make it simpler to try out DDN, by starting with a mode
that uses no auth.
<!-- What is this PR trying to accomplish (and why, if it's not
obvious)? -->
<!-- Consider: do we need to add a changelog entry? -->
### How
Add a `NoAuth` `AuthConfig` mode that is configured thus:
```json
"noAuth": {
"role": "admin",
"sessionVariables": {
"x-hasura-user-id": "1"
}
}
```
Given the above config:
- If no `x-hasura-role` is sent with a request, we run it as `admin`.
- If a `x-hasura-role` header is sent and it's `admin`, it continues to
work
- If any other `x-hasura-role` header is sent, an error will happen.
- All other headers are ignored, and we always set `x-hasura-user-id` to
1
<!-- How is it trying to accomplish it (what are the implementation
steps)? -->
V3_GIT_ORIGIN_REV_ID: dddcfbee9c3a31e84dfc8013de32e3a9bf31943d
