Dapr dotnet-sdk v1.4.0

Add an option to set Timeout for ActorProxy (#748)

* Add an option to set Timeout for ActorProxy

Actors, by there nature, may have to wait for a long period before
being allowed to execute. This could lead to long request times. The
default timeout for the HttpClient being used is fairly low. This
commit allows for the timeout to be set when constructing the
proxy.

https://github.com/dapr/dotnet-sdk/issues/728

* Removed extra constructor and e2e tests.