[ws-manager-mk2] Add duration validation

[WVerlaek]

Description

Add validation on the duration field. The format=duration annotation is too lenient and still accepts some duration formats that can't be parsed by time.ParseDuration, so instead we can set a regex as described in kubernetes/apiextensions-apiserver#56

Fixes an invalid duration breaking the controller list/watch, stopping reconciliation of all workspace resources.

Related Issue(s)

Part of #11416

How to test

In a preview env:

• gp set timeout 2h, try for various timeout values/units, and observe all succeed
• kubectl edit workspace <name> and manually set an invalid timeout value in spec.timeout.time, and check that the update gets rejected by the API server

Release Notes

NONE

Documentation

Build Options:

• /werft with-github-actions
  Experimental feature to run the build with GitHub Actions (and not in Werft).
• leeway-no-cache
  leeway-target=components:all
• /werft no-test
  Run Leeway with --dont-test

Publish Options

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

Installer Options

• with-ee-license
• with-dedicated-emulation
• with-ws-manager-mk2
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment Options:

• /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
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh