Enable users to easily run samples in Cloud

[josh-berry]

Describe the solution you'd like

From Spencer and Maxim:

We should have a defaultConnection() type static method in all the SDKs that uses localhost by default but, if some file path/env vars/etc are provided, will use those to connect to cloud.

Idea being people can run all our samples easily locally, and then make this ~/.config/temporalconnection file or whatever and boom now it switches to connecting to cloud.

Per-SDK Tickets

• [ ] Go - https://github.com/temporalio/sdk-go/issues/1442
• [ ] Java - https://github.com/temporalio/sdk-java/issues/2035
• [ ] Core - https://github.com/temporalio/sdk-core/issues/717
• [ ] TypeScript - https://github.com/temporalio/sdk-typescript/issues/1395
• [ ] Python - https://github.com/temporalio/sdk-python/issues/509
• [ ] .NET - https://github.com/temporalio/sdk-dotnet/issues/219
• [ ] PHP - https://github.com/temporalio/sdk-php/issues/420

Samples Tickets

• [ ] Go - https://github.com/temporalio/samples-go/issues/341
• [ ] Java - https://github.com/temporalio/samples-java/issues/613
• [ ] .NET - https://github.com/temporalio/samples-dotnet/issues/62
• [ ] TypeScript - https://github.com/temporalio/samples-typescript/issues/359
• [ ] Python - https://github.com/temporalio/samples-python/issues/109
• [ ] PHP - https://github.com/temporalio/samples-php/issues/53

[cretz]

This should all depend on https://github.com/temporalio/features/issues/441, where a proper generally-applicable design needs to be made.