Add timeout API for tasks

### Code of Conduct

- [x] I agree to follow Django's Code of Conduct

### Feature Description

Tasks should support being defined with a timeout:

```python
@task(timeout=30)
def long_running_task():
time.sleep(60)
```

The above task will fail, because it takes longer than 30 seconds.

Timeouts are defined in the `task` decorator in seconds (as an `int - no fractional timeouts). They cannot be configured at enqueue time (with `.using`).

Tasks which timeout are marked as `FAILED`. Once marked as failed, they are subject to retry functionality (see #142). The exception detail will be an instance of a new `TaskTimeout` exception (which subclasses Python's `TimeoutError`).

### Problem

Currently, a task can take an undefined about of time, consuming resources for the queue worker. Usually, this is an error.

### Request or proposal

proposal

### Additional Details

_No response_

### Implementation Suggestions

I gave [a talk about some ways to implement this](https://theorangeone.net/talks/forcefully-stopping-python/) at PyCon UK, but these are out of scope of this discussion.

Tasks are given a timeout by default of 1 hour. In most cases, this is far longer than they will reasonably take, but ensures that internally there's an upper limit after which a task won't be running. This allows backends to use the timeout to indicate when a worker may have dropped a task and stop it sitting in limbo (see https://github.com/RealOrangeOne/django-tasks-db/issues/5). If a task is "RUNNING" after the timeout time (plus some padding, it is considered safe to consider failed).