Support for dual SBOM generation

[prabhu]

Currently, cdxgen generates pre-build/build SBOM for most applications. What if we add an argument to make the tool generate a post-build SBOM in addition to the current one? This way, we can understand both what is built and what is shipped.

To successfully generate a post-build SBOM, we need the application to be built; the user can run cdxgen as a post-build step in the CI to avoid the need for an automatic build. We can also request a specific binary directory for post-build SBOM purposes, which could be excluded for pre-build/build SBOM.