[Feature Request] Rework search attributes and add list endpoint to client

[cretz]

Describe the solution you'd like

• Need to support individual, per-type search attributes and only allow collections for keywords
• Expose workflow listing API on client which should be a lazy iterator

See temporalio/proposals#67

[cretz]

(accidentally closed, reopened)

[bergundy]

@cretz this should still be open, we need to rework search attributes too.

[cretz]

Sorry, I said I reopened but closed again by accident

[cretz]

This is now a duplicate of #381 (and #366)