[ws-proxy] Implement graceful shutdown

[aledbf]

Summary generated by Copilot

🤖 Generated by Copilot at b7bf7f2

This pull request improves the reliability and performance of the workspace proxy by using contexts, goroutines, and graceful shutdowns. It also refactors some code in the cmd and proxy packages to simplify imports and logging.

Related Issue(s)

Fixes ENG-724

How to test

Preview status

Gitpod was successfully deployed to your preview environment.

• 🏷️ Name - aledbf-shutdown
• 🔗 URL - aledbf-shutdown.preview.gitpod-dev.com/workspaces.
• 📚 Documentation - See our internal documentation for information on how to interact with your preview environment.
• 📦 Version - aledbf-shutdown-gha.15903

Build Options

Build

• /werft with-werft
  Run the build with werft instead of GHA
• leeway-no-cache
• /werft no-test
  Run Leeway with --dont-test

Publish

• /werft publish-to-npm
• /werft publish-to-jb-marketplace

Installer

• analytics=segment
• with-dedicated-emulation
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment / Integration Tests

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-gce-vm
  If enabled this will create the environment on GCE infra
• with-integration-tests=workspace
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh. If enabled, with-preview and with-large-vm will be enabled.
• with-monitoring

/hold