IONOS(github): add SBOM generation workflow

1. Generate SBOMs for composer and NPM dependencies
2. Merge composer + NPM into one SBOM
3. Upload the SBOM to dependency track

== NPM SBOMs

SBOMS can be generated without installing dependencies. However, the
SBOMs would not contain description and source information, which is
only available after install of the dependencies.

== Merged SBOM

The merged SBOM may contain invalid values derived from the branch name,
which prevents the SBOM from being uploaded. This is fixed using an awk
command after merge.

== CycloneDX

cyclonedx-cli is used as container image. It was pushed from its
original source [1] into our container registry.

[1]: https://github.com/CycloneDX/cyclonedx-cli?tab=readme-ov-file#docker-image

Signed-off-by: Thomas Lehmann <t.lehmann@strato.de>

Author: thlehmann-ionos