[Feature] Write a conversion layer to help transfer SBOM between SPECS

[riteshnoronha]

Each input & output adapters should know the limitations of the system they are interfacing with. The conversion layer will serve as an adapter to help move sboms from one system to another. Conversion lose data between spec conversions, we should always warn user when this happens.

Use Case:

• User would like to transfer github api generated sboms to DT, github api only generates sboms in SPDX, while DT supports cyclonedx.
• User would like to transfer Cyclonedx 1.6 sboms to a system that does not supports only Cyclonedx 1.4, we should be able to downgrade the version and push it.