move out bitbucket into a separate module too

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

docs/integrations/bitbucket/discovery.md

@@ -11,6 +11,34 @@ catalog entities located in Bitbucket. The processor will crawl your Bitbucket
 account and register entities matching the configured path. This can be useful
 as an alternative to static locations or manually adding things to the catalog.
 
+## Installation
+
+You will have to add the processor in the catalog initialization code of your
+backend. The provider is not installed by default, therefore you have to add a
+dependency to `@backstage/plugin-catalog-backend-module-bitbucket` to your backend
+package.
+
+```bash
+# From your Backstage root directory
+cd packages/backend
+yarn add @backstage/plugin-catalog-backend-module-bitbucket
+```
+
+And then add the processor to your catalog builder:
+
+```diff
+// In packages/backend/src/plugins/catalog.ts
++import { BitbucketDiscoveryProcessor } from '@backstage/plugin-catalog-backend-module-bitbucket';
+
+ export default async function createPlugin(
+   env: PluginEnvironment,
+ ): Promise<Router> {
+   const builder = await CatalogBuilder.create(env);
++  builder.addProcessor(
++    BitbucketDiscoveryProcessor.fromConfig(env.config, { logger: env.logger })
++  );
+```
+
 ## Self-hosted Bitbucket Server
 
 To use the discovery processor with a self-hosted Bitbucket Server, you'll need
@@ -137,14 +165,11 @@ matching repository is processed.
 repository.
 
 ```typescript
-const customRepositoryParser: BitbucketRepositoryParser =
-  async function* customRepositoryParser({ client, repository }) {
-    // Custom logic for interpret the matching repository.
-    // See defaultRepositoryParser for an example
-  };
-
 const processor = BitbucketDiscoveryProcessor.fromConfig(env.config, {
-  parser: customRepositoryParser,
+  parser: async function* customRepositoryParser({ client, repository }) {
+    // Custom logic for interpreting the matching repository.
+    // See defaultRepositoryParser for an example
+  },
   logger: env.logger,
 });
 ```