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 - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-go#1442
• Java - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-java#2035
• Core - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-core#717
• TypeScript - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-typescript#1395
• Python - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-python#509
• .NET - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-dotnet#219
• PHP - Expose defaultConnection() method to switch between localhost and cloud based on env sdk-php#420

Samples Tickets

• Go - Allow users to switch between cloud and localhost when running samples samples-go#341
• Java - Allow users to switch between cloud and localhost when running samples samples-java#613
• .NET - Allow users to switch between cloud and localhost when running samples samples-dotnet#62
• TypeScript - Allow users to switch between cloud and localhost when running samples samples-typescript#359
• Python - Allow users to switch between cloud and localhost when running samples samples-python#109
• PHP - Allow users to switch between cloud and localhost when running samples samples-php#53

[cretz]

This should all depend on #441, where a proper generally-applicable design needs to be made.