Add tamr-client continuous mastering tutorial

[skalish]

↪️ Pull Request

This PR adds a Continuous Mastering tutorial that describes how to programmatically keep a Tamr Mastering project up to date using tamr-client.

Closes #449

✔️ PR Todo

• [x] Included links to related issues/PRs
• [x] Update relevant docs + docstrings
• [x] Update the CHANGELOG under the current -dev version:
  • Add changelog entries under any that apply: BREAKING CHANGES, NEW FEATURES, BUG FIXES.
  • Changelog entry format: [#<issue number>](<link to issue>) <change description>

Screenshots of Built Docs

[skalish]

The typechecking of the example script is giving me a hard time here.

examples/continuous_mastering.py:19: error: Argument 2 to "update_unified_dataset" has incompatible type "Union[CategorizationProject, MasteringProject, SchemaMappingProject, GoldenRecordsProject]"; expected "MasteringProject"

I retrieve a project using tc.project.by_name() which mypy detects as a Project, however, the mastering functions specifically expect a MasteringProject. In real operation, the project type would be interpreted from the retrieved JSON and this issue would not occur, but this is an issue for example scripts.

[skalish]

@lamagnifica @Lordluen don't hold back with any comments or criticism here. I'm happy to make any and all changes to get this as right as possible, since this tutorial will likely serve as a model to inform the style and wording of tutorials contributed in the future.

[pcattori]

@lamagnifica @Lordluen : we've merged this PR. The expectation going forward is that dev will include docs team on PRs that add/modify docs, but will not be blocked by docs review on them to merge. Docs team can then leave feedback posthoc and will also have access to these docs live @ tamr-client.readthedocs.io so that review can be simpler.

Any docs issues encountered can be opened up as tickets / PRs.

[lamagnifica]

@lamagnifica @Lordluen : we've merged this PR. The expectation going forward is that dev will include docs team on PRs that add/modify docs, but will not be blocked by docs review on them to merge. Docs team can then leave feedback posthoc and will also have access to these docs live @ tamr-client.readthedocs.io so that review can be simpler.

Any docs issues encountered can be opened up as tickets / PRs.

Totally fine by me, @pcattori. In future, please just give me either a heads up that a draft is coming for review or a timeframe to complete the review prior to merge.