Add benchmarking test suite and greatly improve performance in a few cases (#948)

* Add benchmarking test suite

* Improve amortized time of model relation loads with a large number of rows

* Improve performance of loading models with many related models

* Improve performance of loading models with many related models to O(N)ish

* Fix bug where N model creation with shared related model would build in N^2 time

* Lower blocking time for queryset results

* Add docstrings and streamline hash code

Co-authored-by: haydeec1 <Eric.Haydel@jhuapl.edu>

.github/workflows/test-package.yml

@@ -65,7 +65,7 @@ jobs:
       env:
         DATABASE_URL: "sqlite:///testsuite"
       run: bash scripts/test.sh
-    - run: mypy ormar tests
+    - run: mypy ormar tests benchmarks
     - name: Upload coverage
       uses: codecov/codecov-action@v3.1.1
     - name: Test & publish code coverage