Add datawire-envoy

[wlynch]

This is a fork of envoy with patches applied by Ambassador for their emissary project.
See https://github.com/emissary-ingress/emissary/blob/ac2dc64c6621cd8ec5617f3328544364bdd3fb01/DevDocumentation/ARCHITECTURE.md#envoy

The only modification here from base envoy is the source location. These should try and stay in sync, but I don't know if there's a better way to represent this.

Related: https://github.com/chainguard-dev/image-requests/issues/3494

Pre-review Checklist

For new package PRs only

• This PR is marked as fixing a pre-existing package request bug
  • Alternatively, the PR is marked as related to a pre-existing package request bug, such as a dependency
• REQUIRED - The package is available under an OSI-approved or FSF-approved license
• REQUIRED - The version of the package is still receiving security updates
• This PR links to the upstream project's support policy (e.g. endoflife.date)

For new version streams

• The upstream project actually supports multiple concurrent versions.
• Any subpackages include the version string in their package name (e.g. name: ${{package.name}}-compat)
• The package (and subpackages) provides: logical unversioned forms of the package (e.g. nodejs, nodejs-lts)
• If non-streamed package names no longer built, open PR to withdraw them (see WITHDRAWING PACKAGES)

I believe this supports the same upstream version streams as envoy.