move widget to its own package

Signed-off-by: Kiss Miklos <miklos@roadie.io>

plugins/api-docs-react/README.md

@@ -0,0 +1,40 @@
+# @backstage/plugin-api-docs-react
+
+### Setup
+
+This widget will render the generated `protoc-gen-doc` descriptors with the `grpc-docs` package. For this make sure you use the `grpc-docs` as the type in the API catalog file.
+
+```yaml
+spec:
+  type: grpc-docs
+  owner: foo
+  definition:
+    $text: https://fetch-my-json.com/awesome-resource.json
+```
+
+### Add the GrpcDocsApiWidget to your apis
+
+Add the widget to your `apiDocsConfigRef` in the following way. Make sure the `apiEntity.spec.type` is compared to `grpc-docs`
+
+```ts
+// packages/app/apis.ts
+  createApiFactory({
+    api: apiDocsConfigRef,
+    deps: {},
+    factory: () => {
+      // load the default widgets
+      const definitionWidgets = defaultDefinitionWidgets();
+      return {
+        getApiDefinitionWidget: (apiEntity: ApiEntity) => {
+          // custom rendering for grpc-docs
+          if (apiEntity.spec.type === 'grpc-docs') {
+            return grpcDocsApiWidget();
+          }
+
+          // fallback to the defaults
+          return definitionWidgets.find(d => d.type === apiEntity.spec.type);
+        },
+      };
+    },
+  }),
+```