prefect-dbt: from_file method for PostgresTargetConfig

[robfreedy]

First check

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Prefect Version

2.x

Describe the current behavior

Currently, you have to define a PostgresTargetConfigs block with Postgres database configurations manually in python code or in the Prefect UI, which can then get passed to the DbtCliProfile to save the credentials. This usually means a lot of copying and pasting from the dbt profiles.yml or elsewhere.

Describe the proposed behavior

Add a from_file method to the PostgresTargetConfigs block to automatically populate the credentials and config into a new instance of a PostgresTargetConfig block given an existing dbt profiles.yml file.

Example Use

postgres_target_config = PostgresTargetConfgs.from_file(file_path="/path/to/profileyaml/.dbt/profile.yml")
dbt_cli_profile = DbtCliProfile(
            name="jaffle_shop",
            target="dev",
            target_configs=postgres_target_config,
        )

Additional context

No response