Release v0.4.0

What's Changed

• expand description section of readme; document release process by @dgrove-oss in #29
• expand opening paragraph of README by @dgrove-oss in #30
• Update to use Kubernetes 1.27.1 for testing by @dgrove-oss in #31
• unit tests for Controllers by @dgrove-oss in #32
• improve unit test: reconcile twice to fully exercise deletion processing by @dgrove-oss in #33
• enforce appwrapper components is immutable except to AW controller by @dgrove-oss in #34
• initial batch of end-to-end tests by @dgrove-oss in #35
• cleanup todos; add issue links by @dgrove-oss in #37
• customize kueue configuration by @dgrove-oss in #38
• Improvements in e2e testing by @dgrove-oss in #39
• improvements in test cluster creation by @dgrove-oss in #40
• factor out controller initialization logic by @dgrove-oss in #41
• hacks to avoid dockerhub rate limits during CI by @dgrove-oss in #42
• update testing section of README by @dgrove-oss in #43

Full Changelog: v0.3.2...v0.4.0