ci: Move devbuilds to test workflow. Upload artifacts from test builds. Merge Dockerfiles and clone based on ARG BRANCH_OR_TAG. Change prefix of dependabot branch names

Bumps lsiobase/nginx from 3.14 to 3.15-php8-version-ef5b8f3b.

---
updated-dependencies:
- dependency-name: lsiobase/nginx
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps node from 16.9.1-alpine3.13 to 16.10.0-alpine3.13.

---
updated-dependencies:
- dependency-name: node
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps node from 16.6.1-alpine3.13 to 16.9.1-alpine3.13.

---
updated-dependencies:
- dependency-name: node
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>