Access Policy Share Asset example code and Notebook

What's Changed

• SBOM metadata has tenantid field by @eccles in #165
• Unittest docstrings by @eccles in #169
• BEHAVIOURS constant in wrong place. by @eccles in #168
• Access policies count_matching methods by @eccles in #167
• Misnamed arguments to subjects endpoint by @eccles in #166
• Example code for sharing an asset by @eccles in #170

Full Changelog: v0.16.0...v0.17.0