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/botPolicies.yaml

@@ -43,10 +43,7 @@ bots:
 #     report_as: 4    # lie to the operator
 #     algorithm: slow # intentionally waste CPU cycles and time
 
-# Generic catchall rule
-- name: generic-browser
-  user_agent_regex: >-
-    Mozilla|Opera
-  action: CHALLENGE
+# Challenge things that claim to be a browser but are not
+- import: (data)/common/challenge-browser-like.yaml
 
 dnsbl: false

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

data/common/challenge-browser-like.yaml

@@ -0,0 +1,16 @@
+  # Challenge anything with HTTP/1.1 that claims to be a browser
+  - name: challenge-lies-browser-but-http-1.1
+    action: CHALLENGE
+    expression:
+      all:
+      - '"X-Http-Version" in headers'
+      - headers["X-Http-Version"] == "HTTP/1.1"
+      - >-
+        (  userAgent.contains("Mozilla")
+        || userAgent.contains("Opera")
+        || userAgent.contains("Safari")
+        || userAgent.contains("Edge")
+        || userAgent.contains("Gecko")
+        || userAgent.contains("Windows")
+        || userAgent.contains("Linux")
+        )

data/common/legacy-challenge-everything.yaml

@@ -0,0 +1,5 @@
+# Generic catchall rule
+- name: generic-browser
+  user_agent_regex: >-
+    Mozilla|Opera
+  action: CHALLENGE