As a user I want to be able to import xml OSCAL artifacts into trestle using trestle import

[butler54]

Issue description / feature objectives

trestle focuses on json and yaml for OSCAL support, however, 3rd party objects may exist in XML form. Given that NIST are producing XSLT transforms which require XSLT 3.0 the recommendation is that we use this functionality (together with Saxon-HE) via a CLI escape.

Artifacts will be imported into trestle in either json or yaml format.

Note: This functionality will require users to manually install saxon-HE. On absence of the library users should be directed to documentation on how to install themselves.

Completion Criteria

• Import functions with Saxon-HE when present via CLI wrapping
• Functionality and requirements are well documented.
• CI-CD pipeline is updated to test functionality including automatically pulling the appropriate upstream java libraries for testing.

Steps to Reproduce the Problem

Specifications

• Version / branch:
• Platform:
• Subsystem:

[butler54]

Updating based on the conversation around #249.
It should be possible to do this via a similar model to #249 (potentially using the same scripts to download and manage a local saxon copy).

Expectation is that a collaboration with the 10X team may make this fesiable.

[butler54]

Duplicate of #178