Add patch.estimates methods for GLEC-certified shipping estimates

[holtbp]

What

• Adds patch.estimates.create_air_shipping_estimate method
• Adds patch.estimates.create_rail_shipping_estimate method
• Adds patch.estimates.create_road_shipping_estimate method
• Adds patch.estimates.create_sea_shipping_estimate method

Why

To provide GLEC-certified shipping estimates!

SDK Release Checklist

• Have you added an integration test for the changes?
• Have you built the library locally and made queries against it successfully?
• Did you update the changelog?
• Did you bump the package version?
• If endpoints were removed, did you manually remove the corresponding files? (this should be rare)
• For breaking changes, did you plan for the release of the new SDK versions and deploy the API to production?