ci: Split READMEs, add missing docs for CREATE_SNAPSHOT env variable

Author: Stephan Wentz

README.console-trait.md

@@ -0,0 +1,5 @@
+# brainbits Functional Test Helpers
+
+## Console Trait
+
+todo...

README.http-client-trait.md

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+# brainbits Functional Test Helpers
+
+## HTTP Client Trait
+
+To use the mock http client, configure the `MockRequestBuilderCollection` as `mock_response_factory` in the framework configuration section.
+
+Example symfony config:
+
+```yaml
+# config/packages/http_client.yaml
+when@test:
+    services:
+        Brainbits\FunctionalTestHelpers\HttpClientMock\MockRequestBuilderCollection:
+            arguments:
+                - '@Brainbits\FunctionalTestHelpers\HttpClientMock\SymfonyMockResponseFactory'
+
+        Brainbits\FunctionalTestHelpers\HttpClientMock\SymfonyMockResponseFactory: ~
+```
+
+```yaml
+# config/packages/framework.yaml
+when@test:
+    framework:
+        test: true
+        http_client:
+            mock_response_factory: 'Brainbits\FunctionalTestHelpers\HttpClientMock\MockRequestBuilderCollection'
+```
+
+In your test, you can provide mock responses, which will be matched by the given mock requests.
+
+```php
+// MyTest.php
+
+public function testRequest(): void
+{
+    $this->mockRequest('GET', 'http://127.0.0.1/my/endpoint')
+        ->willRespond($this->mockResponse()->json([]));
+    
+    // ...
+
+    Assert::assertNotEmpty($this->callStack()->first);
+}
+
+```