added schema field, and search_path lookup, fixes #163

[yuriy-yarosh]

PR Info

• Closes: Improve postgresql schema discovery by tolerating search_path setting #163 Duplicate Postgres enums across schemas #142
• Dependents: a refactored (de-slopified) version of seaorm/2745, which comes next

New Features

• Performs enums lookup using all schemas in search_path pg_settings
• Returns schema name in enum struct, for further filtering in codegen CLI, so only the current schema enums will be persisted into models

Breaking Changes

• Added schema field into EnumDef, which is a minor bump

Changes

• Added discover_search_path discover_search_path_with for the search_path pg_setting.
• Updated tests/discovery/postgres/schema.rs snapshot a bit, to reflect that we're getting public namespace in the enum. It's old and stale, and should be refactored and replaced with some golden files in goldie or similar.
• Added sqlx-postgres SqlxRow casts.

[yuriy-yarosh]

We'll need to adopt this approach later for other types and domains, as well...