Remove (mostly) unused AppBundle code from webpushd. It's only used for some API tests, but those API tests are exercising a feature that isn't shipping, and can also be removed.
<rdar://problem/114283091>
Pull request: https://github.com/WebKit/WebKit/pull/16948
Committed 267168@main (fe2039934e79): <https://commits.webkit.org/267168@main> Reviewed commits have been landed. Closing PR #16948 and removing active labels.