add passreset routes

Introduced `get|post` `/passreset` routes. These routes mimic the
behavior of the existing PHP implementation, with the exception of
HTTP status code returns.

Routes added:
    GET /passreset
    POST /passreset

Routers added:
    aurweb.routers.accounts

* On an unknown user or mismatched resetkey (where resetkey must ==
  user.resetkey), return HTTP status NOT_FOUND (404).
* On another error in the request, return HTTP status BAD_REQUEST (400).

Both `get|post` routes requires that the current user is **not**
authenticated, hence `@auth_required(False, redirect="/")`.

+ Added auth_required decorator to aurweb.auth.
+ Added some more utility to aurweb.models.user.User.
+ Added `partials/error.html` template.
+ Added `passreset.html` template.
+ Added aurweb.db.ConnectionExecutor functor for paramstyle logic.
  Decoupling the executor logic from the database connection logic
  is needed for us to easily use the same logic with a fastapi
  database session, when we need to use aurweb.scripts modules.

At this point, notification configuration is now required to complete
tests involved with notifications properly, like passreset.
`conf/config.dev` has been modified to include [notifications] sendmail,
sender and reply-to overrides. Dockerfile and .gitlab-ci.yml have been
updated to setup /etc/hosts and start postfix before running tests.

* setup.cfg: ignore E741, C901 in aurweb.routers.accounts

These two warnings (shown in the commit) are not dangerous and a bi-product
of maintaining compatibility with our current code flow.

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

aurweb/routers/auth.py

@@ -6,6 +6,7 @@ from fastapi.responses import HTMLResponse, RedirectResponse
 
 import aurweb.config
 
+from aurweb.auth import auth_required
 from aurweb.models.user import User
 from aurweb.templates import make_context, render_template
 
@@ -21,12 +22,13 @@ def login_template(request: Request, next: str, errors: list = None):
 
 
 @router.get("/login", response_class=HTMLResponse)
+@auth_required(False)
 async def login_get(request: Request, next: str = "/"):
-    """ Homepage route. """
     return login_template(request, next)
 
 
 @router.post("/login", response_class=HTMLResponse)
+@auth_required(False)
 async def login_post(request: Request,
                      next: str = Form(...),
                      user: str = Form(default=str()),
@@ -45,8 +47,8 @@ async def login_post(request: Request,
         cookie_timeout = aurweb.config.getint(
             "options", "persistent_cookie_timeout")
 
-    _, sid = user.login(request, passwd, cookie_timeout)
-    if not _:
+    sid = user.login(request, passwd, cookie_timeout)
+    if not sid:
         return login_template(request, next,
                               errors=["Bad username or password."])
 
@@ -62,6 +64,7 @@ async def login_post(request: Request,
 
 
 @router.get("/logout")
+@auth_required()
 async def logout(request: Request, next: str = "/"):
     """ A GET and POST route for logging out.
 
@@ -81,5 +84,6 @@ async def logout(request: Request, next: str = "/"):
 
 
 @router.post("/logout")
+@auth_required()
 async def logout_post(request: Request, next: str = "/"):
     return await logout(request=request, next=next)