Bake Python 3.11, node 18 and PHP 8.1 into bullseye GitHub Actions build image

[cormacpayne]

At the request of the Antares team, we are baking the following platform versions into the bullseye flavor of the GitHub Actions build image:

• Python 3.11
• node 18
• PHP 8.1

This is a temporary change until PR https://github.com/microsoft/Oryx/pull/1484 is merged to allow us to choose which Debian flavor of an SDK we dynamically install onto a build image.

The PHP 8.1 binaries needed to be published to the development storage account for easiest consumption within the build image and will be removed as soon as these changes are reverted.

• [x] The purpose of this PR is explained in this message or in an issue. If an issue please include a reference as #<issue_number>. ~- [ ] Tests are included and/or updated for code changes.~ ~- [ ] Proper license headers are included in each file.~