feature: Add provided certificates check before to generate ACME certificate when OnHostRule is activated

- ADD TI to check the new behaviour with onHostRule and provided certificates
- ADD TU on the getProvidedCertificate method

integration/fixtures/acme/acme_provided.toml

@@ -0,0 +1,35 @@
+logLevel = "DEBUG"
+
+defaultEntryPoints = ["http", "https"]
+
+[entryPoints]
+  [entryPoints.http]
+  address = ":8080"
+  [entryPoints.https]
+  address = ":5001"
+    [entryPoints.https.tls]
+      [[entryPoints.https.tls.certificates]]
+      CertFile = "fixtures/acme/ssl/wildcard.crt"
+      KeyFile = "fixtures/acme/ssl/wildcard.key"
+
+[acme]
+email = "test@traefik.io"
+storage = "/dev/null"
+entryPoint = "https"
+onDemand = {{.OnDemand}}
+OnHostRule = {{.OnHostRule}}
+caServer = "http://{{.BoulderHost}}:4000/directory"
+
+[file]
+
+[backends]
+  [backends.backend]
+    [backends.backend.servers.server1]
+    url = "http://127.0.0.1:9010"
+
+
+[frontends]
+  [frontends.frontend]
+  backend = "backend"
+    [frontends.frontend.routes.test]
+    rule = "Host:traefik.acme.wtf"