introduce SBOM operator

What does this MR do and why?

This MR introduces an optional unit sbom-operator, which allows to build the Software Bill Of Material (SBOM) of Sylva. The unit deploys an operator generating the SBOM of each image used in a Sylva cluster. By default, the SBOMs is supposed to be exported to a dependency track instance.

Related reference(s)

This MR meets part of requirements stressed in: https://gitlab.com/sylva-projects/sylva/-/blob/rfe-dt/RFE/rfe-dependency-track.md

Test coverage

Tested on a kubeadm-capo deployment with SBOM sent to confimaps and an external dependency track server.