Sanitize and modernize pytests

Some of these tests were written before some of our convenient
tooling existed. Additionally, some of the tests were not
cooperating with PEP-8 guidelines or isorted.

This commit does the following:
    - Replaces all calls to make_(user|session) with
      aurweb.db.create(Model, ...).
    - Replace calls to session.add(...) + session.commit() with
      aurweb.db.create.
    - Removes the majority of calls to (session|aurweb.db).delete(...).
    - Replaces session.query calls with aurweb.db.query.
    - Initializes all mutable globals in pytest fixture setup().
    - Makes mutable global declarations more concise:
      `var1, var2 = None, None` -> `var1 = var2 = None`
    - Defines a warning exclusion for test/test_ssh_pub_key.py.
    - Removes the aurweb.testing.models module.
    - Removes some useless pytest.fixture yielding.

As of this commit, developers should use the following guidelines
when writing tests:
    - Always use aurweb.db.(create|delete|query) for database
      operations, where possible.
    - Always define mutable globals in the style: `var1 = var2 = None`.
    - `yield` the most dependent model in pytest setup fixture **iff**
      you must delete records after test runs to maintain database
      integrity. Example: test/test_account_type.py.

This all makes the test code look and behave much cleaner.
Previously, aurweb.testing.setup_test_db was buggy and leaving
objects around in SQLAlchemy's IdentityMap.

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

setup.cfg

@@ -2,18 +2,26 @@
 max-line-length = 127
 max-complexity = 10
 
-# Ignore some unavoidable flake8 warnings; we know this is against
-# pycodestyle, but some of the existing codebase uses `I` variables,
-# so specifically silence warnings about it in pre-defined files.
-# In E741, the 'I', 'O', 'l' are ambiguous variable names.
-# Our current implementation uses these variables through HTTP
-# and the FastAPI form specification wants them named as such.
-# In C901's case, our process_account_form function is way too
-# complex for PEP (too many if statements). However, we need to
-# process these anyways, and making it any more complex would
-# just add confusion to the implementation.
+# aurweb/routers/accounts.py
+#   Ignore some unavoidable flake8 warnings; we know this is against
+#   pycodestyle, but some of the existing codebase uses `I` variables,
+#   so specifically silence warnings about it in pre-defined files.
+#   In E741, the 'I', 'O', 'l' are ambiguous variable names.
+#   Our current implementation uses these variables through HTTP
+#   and the FastAPI form specification wants them named as such.
+#   In C901's case, our process_account_form function is way too
+#   complex for PEP (too many if statements). However, we need to
+#   process these anyways, and making it any more complex would
+#   just add confusion to the implementation.
+#
+# test/test_ssh_pub_key.py
+#   E501 is detected due to our >127 width test constant. Ignore it.
+#   Due to this, line width should _always_ be looked at in code reviews.
+#   Anything like this should be questioned.
+#
 per-file-ignores =
     aurweb/routers/accounts.py:E741,C901
+    test/test_ssh_pub_key.py:E501
 
 [isort]
 line_length = 127