Integrate DTS emulator with workspace view

[philliphoff]

Adds a DTS emulator node to the Workspace view of the Azure Resources explorer, which will show running DTS emulator instances. This node offers the ability to start new emulator instances. Emulator nodes, like in the Azure Resources view, offers the abilities:

• Copy connections strings
• Open the corresponding task hub dashboard
• Shutdown the emulator

The DTS settings have been updated to allow customization (i.e. registry, image, tag) of the emulator container image. Emulators started by the VS Code instance will be shutdown when the instance is closed. (Emulators started outside of the VS Code instance will not be shutdown.)

Note: the emulator features are not hidden behind the "preview features" toggle as they are (as of now) available to all.

[nturinski]

Phil, would it be possible to add a command to install/uninstall the emulator similar to Azure Functions Core Tools?

When you activate the extension, it immediately throws an error as well:

I think that it may be a jarring experience for users that do not have the DTS emulator installed or are not engaging with it.

[philliphoff]

@nturinski Thanks for taking a look.

Phil, would it be possible to add a command to install/uninstall the emulator similar to Azure Functions Core Tools?

The emulator is just a Docker container; there's nothing to install or uninstall really (save pulling/removing an image). I'll think about whether we can show/hide the workspace node based on the existence of the image (and then have a command that just pulls it). I feel that's not terribly discoverable, though.

When you activate the extension, it immediately throws an error as well:

Well that's not good; I'll try to repro and resolve that.