Remove Tasks samples (moved to java-tasks) (GoogleCloudPlatform#4050)

Fixes #issue

> It's a good idea to open an issue first for discussion.

- [ ] I have followed [Sample Format Guide](https://github.com/GoogleCloudPlatform/java-docs-samples/blob/master/SAMPLE_FORMAT.md)
- [ ] `pom.xml` parent set to latest `shared-configuration`
- [ ] Appropriate changes to README are included in PR
- [ ] API's need to be enabled to test (tell us)
- [ ] Environment Variables need to be set (ask us to set them)
- [ ] **Tests** pass:   `mvn clean verify` **required**
- [ ] **Lint**  passes: `mvn -P lint checkstyle:check` **required**
- [ ] **Static Analysis**:  `mvn -P lint clean compile pmd:cpd-check spotbugs:check` **advisory only**
- [ ] Please **merge** this PR for me once it is approved.

Author: averikitsch

tasks/README.md

@@ -1,60 +1,3 @@
 # Google Cloud Tasks Samples
 
-This sample demonstrates using the Cloud Tasks client library. These code snippets
-are not executable, but are a copy-and-pasteable resource for your own code
-base. For executable code, see the [App Engine Quickstart](https://cloud.google.com/tasks/docs/quickstart-appengine).
-
-See the [Cloud Tasks documentation](https://cloud.google.com/tasks/docs/) for more info on [Creating HTTP Target tasks](https://cloud.google.com/tasks/docs/creating-http-target-tasks).
-
-`CreateHttpTask.java` constructs a task with an HTTP target and pushes it
-to your queue.
-
-`CreateHttpTask.java` constructs a task with an HTTP target and OIDC token and
-pushes it to your queue.
-
-## Initial Setup
-
- * Set up a Google Cloud Project and enable billing.
- * Enable the
- [Cloud Tasks API](https://console.cloud.google.com/launcher/details/google/cloudtasks.googleapis.com).
- * Download and install the [Cloud SDK](https://cloud.google.com/sdk).
- * Download and install [Maven](http://maven.apache.org/install.html).
- * Set up [Google Application Credentials](https://cloud.google.com/docs/authentication/getting-started).
-
-## Creating a queue
-
-To create a queue using the Cloud SDK, use the following `gcloud` command:
-
-```
-gcloud tasks queues create <QUEUE_NAME>
-```
-
-The location of your queue is the same as your Google Cloud Project. It can be discovered by using the following `gcloud` command:
-
-```
-gcloud tasks queues describe <QUEUE_NAME>
-```
-the location embedded in the "name" value (for instance, if the name is
-"projects/my-project/locations/us-central1/queues/my-queue", then the
-location is "us-central1").
-
-## Creating Tasks with HTTP Targets
-
-Set an endpoint to your task handler by replacing the variable `url` with your
-HTTP target in `CreateHttpTask.java`.
-
-The sample will create a task and add it to your queue. As the queue processes
-each task, it will send the task to the specific URL endpoint.
-
-## Using HTTP Targets with Authentication Tokens
-
-Set an endpoint to your task handler by replacing the variable `url` with your
-HTTP target in `CreateHttpTaskWithToken.java`.
-
-Your Cloud Tasks [service account][sa],
-([email protected]), must
-have the role of: `Service Account Token Creator` to generate a tokens.
-
-Create or use an existing [service account][sa] to authenticate the OIDC token.
-
-[sa]: https://cloud.google.com/iam/docs/service-accounts
+These samples have moved to [googleapis/java-tasks](https://github.com/googleapis/java-tasks/tree/master/samples).