Review ORM classes and generated SQL queries for improvements

[leafty]

For a example to retrieve a single project, this is what sqlalchemy generates:

INFO     sqlalchemy.engine.Engine:base.py:2701 BEGIN (implicit)
INFO     sqlalchemy.engine.Engine:base.py:1846 SELECT projects.projects.id, projects.projects.name, projects.projects.visibility, projects.projects.created_by_id, projects.projects.description, projects.projects.keywords, projects.projects.creation_date, projects.projects.updated_at, groups_1.id AS id_1, groups_1.name AS name_1, groups_1.created_by, groups_1.creation_date AS creation_date_1, groups_1.description AS description_1, users_1.keycloak_id, users_1.first_name, users_1.last_name, users_1.email, users_1.secret_key, users_1.id AS id_2, namespaces_1.id AS id_3, namespaces_1.slug, namespaces_1.group_id, namespaces_1.user_id, project_slugs_1.id AS id_4, project_slugs_1.slug AS slug_1, project_slugs_1.project_id, project_slugs_1.namespace_id 
FROM projects.projects LEFT OUTER JOIN projects.project_slugs AS project_slugs_1 ON projects.projects.id = project_slugs_1.project_id LEFT OUTER JOIN common.namespaces AS namespaces_1 ON namespaces_1.id = project_slugs_1.namespace_id LEFT OUTER JOIN common.groups AS groups_1 ON groups_1.id = namespaces_1.group_id LEFT OUTER JOIN users.users AS users_1 ON users_1.keycloak_id = namespaces_1.user_id 
WHERE projects.projects.id = $1::VARCHAR
INFO     sqlalchemy.engine.Engine:base.py:1846 [generated in 0.00021s] ('01J9RH5JSX13FPPND9B2EX719C',)
INFO     sqlalchemy.engine.Engine:base.py:1846 SELECT projects.projects_repositories.project_id AS projects_projects_repositories_project_id, projects.projects_repositories.id AS projects_projects_repositories_id, projects.projects_repositories.url AS projects_projects_repositories_url 
FROM projects.projects_repositories 
WHERE projects.projects_repositories.project_id IN ($1::VARCHAR)
INFO     sqlalchemy.engine.Engine:base.py:1846 [generated in 0.00028s] ('01J9RH5JSX13FPPND9B2EX719C',)
INFO     sqlalchemy.engine.Engine:base.py:2704 ROLLBACK

We can see that we should eagerly fetch from projects.projects_repositories since the repository list is immediately needed in dump().