FastAPI: Jinja2 base layout + database models

This MR brings in basic Jinja2 template rendering with l10n integration, as well as basic SQLAlchemy models (starting with User, AccountType).

Coverage Note: With this MR, we're at 86% total coverage across the base. Our goal is 100%, but with this MR, testing coverage was focused primarily on files being added (all new files should be at 100%) and some where we could easily get it. That being said; we expect that all new Python code added for FastAPI should have 100% coverage.

View Changes

First, follow INSTALL for relevant configuration and database setup.

Then, run the FastAPI server in straight up development mode:

$ hypercorn aurweb.asgi:app

With hypercorn running, you can browse to http://localhost:8000. You will be presented with the index page, which uses the entirety of ./templates/ to render through FastAPI. This page has the base layout of the website, without user authentication taken into account, including the set_lang language form located at the top right underneath the main navigation bar.

Additions

• aurweb.models.user, an SQLAlchemy ORM Users table mapping.
• aurweb.models.account_type, an SQLAlchemy ORM AccountTypes table mapping.
• aurweb.routers.html, a router used to render our HTML layout.
• aurweb.templates, a jinja2-based template module.
• aurweb.testing, a test utility module.
• the templates directory.
• aurweb.config [options] aurwebdir, useful to store the absolute root of aurweb in the config so we can just grab its location without introspecting scripts and other workarounds.
• modern pytest suites; see test/*.py.

Modifications

• aurweb.l10n: Make a global Translator object, aurweb.l10n.translator; also added some more utility functions used in different higher level areas.
• test: Added coverage run --append to all Python script executions inside of our shell tests, added pytest suites. This is provided by test/scripts/cover within sharness tests and specified for pytest inside of test/Makefile.
• test/Makefile: Add pytest target, move the check target to sh, use check to cover both pytest and sh.
• .gitlab-ci.yml: Add pytest dependencies, install aurweb, setup a test config and run initdb, then print out coverage report after running make -C test.

For a complete set of modifications, see git log origin/pu..fork/pu_fastapi_base.