feat: add BitbucketCloudEntityProvider (new plugin)

Add a new entity provider `BitbucketCloudEntityProvider`
as a new plugin `@backstage/plugin-catalog-backend-module-bitbucket-cloud`.

The new plugin utilizes `@backstage/plugin-bitbucket-cloud-common`
and it fully independent of `@backstage/plugin-catalog-backend-module-bitbucket`
which provides a catalog processors supporting Bitbucket Cloud and Bitbucket Server.

Relates-to: #9923
Relates-to: #10183
Signed-off-by: Patrick Jungermann <Patrick.Jungermann@gmail.com>

docs/integrations/bitbucketCloud/discovery.md

@@ -0,0 +1,95 @@
+---
+id: discovery
+title: Bitbucket Cloud Discovery
+sidebar_label: Discovery
+# prettier-ignore
+description: Automatically discovering catalog entities from repositories in Bitbucket Cloud
+---
+
+The Bitbucket Cloud integration has a special entity provider for discovering
+catalog files located in [Bitbucket Cloud](https://bitbucket.org).
+The provider will search your Bitbucket Cloud account and register catalog files matching the configured path
+as Location entity and via following processing steps add all contained catalog entities.
+This can be useful as an alternative to static locations or manually adding things to the catalog.
+
+## Installation
+
+You will have to add the entity provider 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-cloud` to your backend
+package.
+
+```bash
+# From your Backstage root directory
+yarn add --cwd packages/backend @backstage/plugin-catalog-backend-module-bitbucket-cloud
+```
+
+And then add the entity provider to your catalog builder:
+
+```diff
+  // In packages/backend/src/plugins/catalog.ts
++ import { BitbucketCloudEntityProvider } from '@backstage/plugin-catalog-backend-module-bitbucket-cloud';
+
+  export default async function createPlugin(
+    env: PluginEnvironment,
+  ): Promise<Router> {
+    const builder = await CatalogBuilder.create(env);
++   builder.addEntityProvider(
++     BitbucketCloudEntityProvider.fromConfig(env.config, {
++       logger: env.logger,
++       schedule: env.scheduler.createScheduledTaskRunner({
++         frequency: { minutes: 30 },
++         timeout: { minutes: 3 },
++       }),
++     }),
++   );
+
+    // [...]
+  }
+```
+
+## Configuration
+
+To use the entity provider, you'll need a [Bitbucket Cloud integration set up](locations.md).
+Very likely a `username` and `appPassword` will be required
+(you are restricted to public repositories and a very low rate limit otherwise).
+
+Additionally, you need to configure your entity provider instance(s):
+
+```yaml
+# app-config.yaml
+
+catalog:
+  providers:
+    bitbucketCloud:
+      yourProviderId: # identifies your ingested dataset
+        catalogPath: /catalog-info.yaml # default value
+        filters: # optional
+          projectKey: '^apis-.*$' # optional; RegExp
+          repoSlug: '^service-.*$' # optional; RegExp
+        workspace: workspace-name
+```
+
+> **Note:** It is possible but certainly not recommended to skip the provider ID level.
+> If you do so, `default` will be used as provider ID.
+
+- **catalogPath** _(optional)_:
+  Default: `/catalog-info.yaml`.
+  Path where to look for `catalog-info.yaml` files.
+  When started with `/`, it is an absolute path from the repo root.
+  It supports values as allowed by the `path` filter/modifier
+  [at Bitbucket Cloud's code search](https://confluence.atlassian.com/bitbucket/code-search-in-bitbucket-873876782.html#Search-Pathmodifier).
+- **filters** _(optional)_:
+  - **projectKey** _(optional)_:
+    Regular expression used to filter results based on the project key.
+  - **repoSlug** _(optional)_:
+    Regular expression used to filter results based on the repo slug.
+- **workspace**:
+  Name of your organization account/workspace.
+  If you want to add multiple workspaces, you need to add one provider config each.
+
+## Alternative
+
+_Deprecated!_ Please raise issues for use cases not covered by the entity provider.
+
+[You can use the `BitbucketDiscoveryProcessor`.](../bitbucket/discovery.md#bitbucket-cloud)

docs/integrations/bitbucketCloud/locations.md

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+---
+id: locations
+title: Bitbucket Cloud Locations
+sidebar_label: Locations
+# prettier-ignore
+description: Integrating source code stored in Bitbucket Cloud into the Backstage catalog
+---
+
+The Bitbucket Cloud integration supports loading catalog entities from [bitbucket.org](https://bitbucket.org).
+Entities can be added to
+[static catalog configuration](../../features/software-catalog/configuration.md),
+or registered with the
+[catalog-import](https://github.com/backstage/backstage/tree/master/plugins/catalog-import)
+plugin.
+
+## Configuration
+
+```yaml
+integrations:
+  bitbucketCloud:
+    - username: ${BITBUCKET_CLOUD_USERNAME}
+      appPassword: ${BITBUCKET_CLOUD_PASSWORD}
+```
+
+> Note: A public Bitbucket Cloud provider is added automatically at startup for
+> convenience, so you only need to list it if you want to supply credentials.
+
+Directly under the `bitbucketCloud` key is a list of provider configurations, where
+you can list the Bitbucket Cloud providers you want to fetch data from.
+In the case of Bitbucket Cloud, you will have up to one entry.
+
+This one entry will have the following elements:
+
+- `username`: The Bitbucket Cloud username to use in API requests. If
+  neither a username nor token are supplied, anonymous access will be used.
+- `appPassword`: The app password for the Bitbucket Cloud user.