Add meal v2 flow and user timezone support

Introduces a new add_meal_v2 blueprint with barcode scanning, item search, and improved meal logging UI. Adds user timezone support: login form now captures timezone, User model and database schema updated, and timezone is set on login. Refactors templates and forms to support these changes, and removes the old login template.

application/auth/routes.py

@@ -1,8 +1,8 @@
-from flask import Blueprint, request, render_template, redirect, url_for
+from flask import Blueprint, render_template, redirect, url_for
 from flask_login import current_user, login_user, logout_user
 from forms import LoginForm, ChangePasswordForm
 from models import User
-from application.utils import default_return
+from application.utils import default_return, is_valid_timezone
 from application import db
 
 bp = Blueprint(
@@ -19,12 +19,16 @@ def login():
 
     form = LoginForm()
     if form.validate_on_submit():
+        assert form.timezone.data
         user = User.query.filter_by(username=form.username.data).first()
         if user and user.check_password(password=form.password.data):
             # User found and password correct
-            next_page = request.args.get("next")  # Get next page if given
+            tz = form.timezone.data
+            if is_valid_timezone(tz):
+                user.set_timezone(tz)
+                db.session.commit()
             login_user(user)  # Log in the user
-            return default_return(next_page=next_page)
+            return default_return()
         else:
             pass
             # invalid user