[server] Remove feature flag workspace_start_controller

[geropl]

Description

Let's merge this after we completely rolled this out

Summary generated by Copilot

🤖 Generated by Copilot at 7b0239c

This pull request removes the legacy code for the workspace start controller and starter, and fully adopts the new implementation. This improves the code quality and consistency of the workspace launch process on Kubernetes.

Related Issue(s)

Fixes EXP-636

How to test

Documentation

Preview status

gitpod:summary

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=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh. If enabled, with-preview and with-large-vm will be enabled.
• with-monitoring

/hold

[geropl]

/unhold