DG-1746 Support custom relationshipDef for any Assets linking

[nikhilbonte21]

Change description

Hagerty (Customer) wants a way to define custom objects that are built on top of Atlan’s Assets interface, create custom definitions for relationships between 2 arbitrary assets and want some properties on the relationship as well.

Overall we try to keep it very generic to make it GA.

• Testing Doc - https://www.notion.so/atlanhq/Custom-relationshipDef-tests-36f5fcc8690744f994c8cd6299dd486c
• Models PR [beta] - https://github.com/atlanhq/models/pull/1152
• A few important considerations - https://atlanhq.atlassian.net/browse/DG-1746?focusedCommentId=184179

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Type of change

• Bug fix (fixes an issue)
• New feature (adds functionality)

Related issues

DG-1746 Support custom relationshipDef for any Assets linking

Checklists

Development

• Lint rules pass locally
• Application changes have been tested thoroughly
• Automated tests covering modified code pass

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

Code review

• Pull request has a descriptive title and context useful to a reviewer. Screenshots or screencasts are attached as necessary
• "Ready for review" label attached and reviewers assigned
• Changes have been reviewed by at least one other contributor
• Pull request linked to task tracker where applicable

[nikhilbonte21]

Continuing #3479