change(fastapi): refactor database ORM model definitions

We don't want to depend on the database to load up data
about the models we define. We now leverage the existing
`aurweb.schema` module for table definitions and set
__table_args__["autoload"] to False.

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/models/package_keyword.py

@@ -1,27 +1,22 @@
-from sqlalchemy import Column, ForeignKey, Integer, String, text
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import backref, relationship
 
+from aurweb import schema
 from aurweb.models.declarative import Base
 from aurweb.models.package_base import PackageBase as _PackageBase
 
 
 class PackageKeyword(Base):
-    __tablename__ = "PackageKeywords"
+    __table__ = schema.PackageKeywords
+    __tablename__ = __table__.name
+    __mapper_args__ = {
+        "primary_key": [__table__.c.PackageBaseID, __table__.c.Keyword]
+    }
 
-    PackageBaseID = Column(
-        Integer, ForeignKey("PackageBases.ID", ondelete="CASCADE"),
-        primary_key=True, nullable=True)
     PackageBase = relationship(
         _PackageBase, backref=backref("keywords", lazy="dynamic",
                                       cascade="all, delete"),
-        foreign_keys=[PackageBaseID])
-
-    Keyword = Column(
-        String(255), primary_key=True, nullable=False,
-        server_default=text("''"))
-
-    __mapper_args__ = {"primary_key": [PackageBaseID, Keyword]}
+        foreign_keys=[__table__.c.PackageBaseID])
 
     def __init__(self, **kwargs):
         super().__init__(**kwargs)