chore(ci): use unified Gitlab pipeline for APM libraries [backport 2.…

…9] (#10529)

**What does this PR do?**
Converts the Gitlab workflow to use the unified pipeline.

By using the unified pipeline across all APM libraries, there is less
maintenance hassle, fewer mistakes, and a more uniform creation of
artifacts.

Additionally, this change creates OCI packages and lib inject images for
every `dd-trace-py` build. Previously, only released versions to pypi
were built and tested.

The changes can be summarized as follows:
* Removing github actions that are now taken over by the unified
pipeline
* Removing Gitlab jobs taken over by the unified pipeline
* Adding a job to download artifacts from the github build
* Merging the download artifacts with dependencies from pypi

`.gitlab-ci.yml` is best reviewed in its final form rather than as a
diff.

**How to test the change?**
The changes were tested manually. CI/CD workflows are notoriously hard
to test. Final products the final lib-init image was run through
automated onboarding tests. `dd-trace-py` doesn't have automated tests
for OCI images

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

---------

Co-authored-by: Laplie Anderson <[email protected]>

.github/workflows/build_deploy.yml

@@ -2,12 +2,6 @@ name: Build
 
 on:
   push:
-    branches:
-      - '[0-9].[0-9]*'
-      - '[0-9].x'
-      # special branches used to test this workflow
-      # before merging/releasing
-      - build_deploy*
   pull_request:
   release:
     types:
@@ -128,12 +122,3 @@ jobs:
           # due to a duplicate wheel being present which will ensure that the rest
           # of the wheels will be uploaded if some are uploaded manually.
           skip_existing: true
-
-  build-and-publish-init-image:
-    needs: [upload_pypi]
-    uses: ./.github/workflows/lib-inject-publish.yml
-    secrets:
-      token: ${{ secrets.GITHUB_TOKEN }}
-    with:
-      ddtrace-version: ${{ github.ref_name }}
-      image-tag: ${{ github.ref_name }}