Continue-as-new with a different WorkflowID

[mfateev]

Is your feature request related to a problem? Please describe.
Workflows that call continue-as-new frequently can lead to hot shards.

Describe the solution you'd like
Many workflows rely on continue-as-new to process large datasets. Many of those workflows do not receive any external signals that require addressing them by WorkflowID.

The proposal is to support an option to continue-as-new to change WorkflowID. The whole chain of workflows still can be navigated through correspondent ids in the events as well listed using visibility queries.