change(aurweb): add parallel tests and improve aurweb.db

This change utilizes pytest-xdist to perform a multiproc test
run and reworks aurweb.db's code. We no longer use a global
engine, session or Session, but we now use a memo of engines
and sessions as they are requested, based on the PYTEST_CURRENT_TEST
environment variable, which is available during testing.

Additionally, this change strips several SQLite components
out of the Python code-base.

SQLite is still compatible with PHP and sharness tests, but
not with our FastAPI implementation.

More changes:
------------
- Remove use of aurweb.db.session global in other code.
- Use new aurweb.db.name() dynamic db name function in env.py.
- Added 'addopts' to pytest.ini which utilizes multiprocessing.
    - Highly recommended to leave this be or modify `-n auto` to
      `-n {cpu_threads}` where cpu_threads is at least 2.

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

test/test_accounts_routes.py

@@ -20,7 +20,6 @@ from aurweb.models.session import Session
 from aurweb.models.ssh_pub_key import SSHPubKey, get_fingerprint
 from aurweb.models.term import Term
 from aurweb.models.user import User
-from aurweb.testing import setup_test_db
 from aurweb.testing.html import get_errors
 from aurweb.testing.requests import Request
 
@@ -50,11 +49,9 @@ def make_ssh_pubkey():
 
 
 @pytest.fixture(autouse=True)
-def setup():
+def setup(db_test):
     global user
 
-    setup_test_db("Users", "Sessions", "Bans", "Terms", "AcceptedTerms")
-
     account_type = query(AccountType,
                          AccountType.AccountType == "User").first()
 
@@ -65,10 +62,6 @@ def setup():
 
     yield user
 
-    # Remove term records so other tests don't get them
-    # and falsely redirect.
-    setup_test_db("Terms", "AcceptedTerms")
-
 
 @pytest.fixture
 def tu_user():