Create the sbom_dependencies table

The sbom dependencies table is intended to act as a higher level definition of a dependency, outside the context of it's use within a ref.

Similar to how the vulnerabilities table is intended, sbom_occurrences will represent a dependency as it occurs within the context of a ref(branch or tag). As such, an occurrence can inherit the static definition of the dependency from the sbom_dependencies table via an appropriately normalized relationship.

This table should include all the columns that define an sbom record, but do not change based on the context of the branch or tag in which it occurs.