feat(data): add challenge-browser-like.yaml

This is a huge change to Anubis and will make it a lot more invisible at
the cost of requiring additional server configuration to make it happen.

If you add this bit of nginx config to your location block:

```nginx
proxy_set_header X-Http-Version $server_protocol;
```

And then adjust the bottom bot rule to this:

```yaml
- import: (data)/common/challenge-browser-like.yaml
```

Anubis will be way less aggressive than it was before. This will let
through any traffic that comes from a browser that actually is a browser
via some more advanced heuristics.

I think that this rule alone is the key feature of v1.18.0.

Signed-off-by: Xe Iaso <me@xeiaso.net>

data/bots/cloudflare-workers.yaml

@@ -1,4 +1,3 @@
 - name: cloudflare-workers
-  headers_regex:
-    CF-Worker: .*
-  action: DENY
+  expression: '"Cf-Worker" in headers'
+  action: CHALLENGE