Batch action for signalling workflows

[varunbpatil]

Is your feature request related to a problem? Please describe.

It will be good to have a batch action for signalling multiple workflows.

Describe the solution you'd like

An implementation similar to all the other batch actions - cancel, terminate, reset.

Describe alternatives you've considered

None

Additional context

I'm open to submitting a PR if this is something you'd like to include.

[varunbpatil]

Eagerly waiting for this feature :)