Revamp all form submissions with Flask-WTF forms

- Rename blueprint route 'main.user' to 'main.view_user' for clarity
- Rename 'forms.py' to 'route_forms.py'

templates/layouts/header.html

@@ -7,7 +7,7 @@
         <div class="header-login">
             {% if current_user.is_authenticated %}
                 Logged in as
-                <a href="{{ url_for('main.user', username=current_user.username) }}" class="username">{{ current_user.username }}</a>
+                <a href="{{ url_for('main.view_user', username=current_user.username) }}" class="username">{{ current_user.username }}</a>
                 <a href="{{ url_for('main.edit_user', username=current_user.username) }}"><i class="fas fa-cog fa-1x"></i></a>
                 | <a href="{{ url_for('auth.logout') }}">Logout</a>
             {% else %}