[Fea] Run function on all workers within an annotate context

`client.run` allows users to pass a list of workers to run a function on specific workers. It would be good if `client.run` could be used in conjunction with the annotate context to run on all workers with a specific resource tag.

Eg:
```python
with dask.annotate(resources={'GPU': 1}):
client.run(gpu_init_func)
```

cc: @jakirkham @beckernick