fixed potential circular imports in formats

[steven11sjf]

• replaced "from mercury_engine_data_structures.formats import BaseResource" with "from mercury_engine_data_structures.formats.base_resource import BaseResource"
• replace "from mercury_engine_data_structures.formats import standard_format" with "from mercury_engine_data_structures.formats.standard_format import <create | game_model> and updated code to remove "standard_format." prefix

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 74.62%. Comparing base (2bff8bc) to head (74908b3).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #182 +/- ## ========================================== + Coverage 74.53% 74.62% +0.09% ========================================== Files 65 65 Lines 3255 3267 +12 ========================================== + Hits 2426 2438 +12 Misses 829 829 ```

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