feat: add associated institutions endpoint, refactored domain parsing

[lchen-2101]

closes #34

[github-actions]

Coverage report

The coverage rate went from 83.51% to 84.32% ⬆️
The branch rate is 86%.

95.23% of new lines are covered.

Diff Coverage details (click to unfold)

src/dependencies.py

83.33% of new lines are covered (82.35% of the complete file).
Missing lines: 43

src/entities/models/init.py

100% of new lines are covered (100% of the complete file).

src/entities/models/dao.py

100% of new lines are covered (100% of the complete file).

src/entities/models/dto.py

100% of new lines are covered (100% of the complete file).

src/entities/repos/institutions_repo.py

100% of new lines are covered (96.82% of the complete file).

src/routers/institutions.py

100% of new lines are covered (100% of the complete file).

[aharjati]

LGTM