Consolidates 6 tests that spun up separate coderdtest instances per sub-test into a single shared instance per parent.
> 🤖 This PR was created with the help of Coder Agents, and has been
reviewed by my human. 🧑💻
This pull request introduces support for external workspace management, allowing users to register and manage workspaces that are provisioned and managed outside of the Coder.
Depends on: https://github.com/coder/terraform-provider-coder/pull/424
* GET /api/v2/init-script - Gets the agent initialization script
* By default, it returns a script for Linux (amd64), but with query parameters (os and arch) you can get the init script for different platforms
* GET /api/v2/workspaces/{workspace}/external-agent/{agent}/credentials - Gets credentials for an external agent **(enterprise)**
* Updated queries to filter workspaces/templates by the has_external_agent field
Cian Johnston