generate file directives for standalone mode

[datdao]

This pull request adds support for parsing file directives in standalone mode. Currently, only table line_number directives are supported.

-- atlas:pos user_account[type=table] tests/models/models.py:10
-- atlas:pos address[type=table] tests/models/models.py:23

CREATE TABLE user_account (id SERIAL NOT NULL, name VARCHAR(30) NOT NULL, fullname VARCHAR(30), PRIMARY KEY (id));

CREATE TABLE address (id SERIAL NOT NULL, email_address VARCHAR(30) NOT NULL, user_id INTEGER NOT NULL, PRIMARY KEY (id), FOREIGN KEY(user_id) REFERENCES user_account (id));

The parser now supports the following SQLAlchemy declarative styles:

• Class-based declaration:

class User(Base):
    __tablename__ = "user_account"

• Object-based declaration:

users = Table(
    "user_account",
)

[ronenlu]

👍