Add plumbing to collect packages from SPDX 2.2 files

[DaveTryon]

This PR is all about adding the IMergeableContentProvider interface, but includes some housekeeping. Specifically, it restructures the ./samples` folder to include both SPDX 2.2 and SPDX 3.0 files. These files were built against the win64 4.0.3 release, using the win 64 tool from the same release. These samples are available for tests

It also adds a functional SPDX 2.2 implementation of IMergeableContentProvider (enabled via dependency injection) and a placeholder SPDX 3.0 implementation of IMergeableContentProvider (not yet in dependency injection).

The SbomConsolidationWorkflow.SourceSbomsTemp property is a test stub that will be removed in the near future.

This code does not yet include plumbing to pass the SBOMs discovered during validation, or plumbing to capture the MergeableContent in the generation workflow.

[github-actions]

This PR changes files in the API project. Does it change any of the API interfaces in any way? Please note that this includes the following types of changes:

• Changing the signature of an existing interface method
• Adding a new method to an existing interface
• Adding a required data member to a class that an existing interface method consumes

Because any of these changes can potentially break a downstream consumer with customized interface implementations, these changes need to be treated as breaking changes. Please do one of the following:

Option 1 - Publish this as a breaking change

1. Update the documentation to show the new functionality
2. Bump the major version in the next release
3. Be sure to highlight the breaking changes in the release notes

Option 2 - Refactor the changes to be non-breaking

1. Review this commit, which adds a new interface in a backward-compatible way
2. Refactor the change to follow this pattern so that existing interfaces are left completely intact
3. Bump the minor version in the next release

[github-actions]

This PR changes files in the API project. Does it change any of the API interfaces in any way? Please note that this includes the following types of changes:

• Changing the signature of an existing interface method
• Adding a new method to an existing interface
• Adding a required data member to a class that an existing interface method consumes

Because any of these changes can potentially break a downstream consumer with customized interface implementations, these changes need to be treated as breaking changes. Please do one of the following:

Option 1 - Publish this as a breaking change

1. Update the documentation to show the new functionality
2. Bump the major version in the next release
3. Be sure to highlight the breaking changes in the release notes

Option 2 - Refactor the changes to be non-breaking

1. Review this commit, which adds a new interface in a backward-compatible way
2. Refactor the change to follow this pattern so that existing interfaces are left completely intact
3. Bump the minor version in the next release

[DaveTryon]

/azp run