Merge Order entity and schema files

[fmrsabino]

• Merges the OrderSchema with the Order entity (on a file level).
• The main reason for this change is that most of the entities are a single-line Zod call to infer the schema. By merging both the schema and the entity we reduce the level of indirection for navigating the project (the schema is the core component of the entity).

[coveralls]

Pull Request Test Coverage Report for Build 8376634212

Details

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 93.347%

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Totals
Change from base Build 8372182365:	0.02%
Covered Lines:	6461
Relevant Lines:	6677

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💛 - Coveralls

The base branch was changed.