Localization support

Localization support. Finnish language added as a second language for the system. Also fixed an issue that could have shown direct error messages to the end users.

Needs testing before merge

src/tjts5901/templates/auth/login.html

 {% extends 'base.html' %}
 
 {% block header %}
-  <h1>{% block title %}Log In{% endblock %}</h1>
+  <h1>{% block title %}{{_("Log In")}}{% endblock %}</h1>
 {% endblock %}
 
 {% block content %}
@@ -12,14 +12,14 @@
             <div class="col-12 d-flex align-items-center justify-content-center">
                 <div class="card card-tertiary w-100 fmxw-400">
                     <div class="card-header text-center">
-                        <span>Sign in to our platform</span>
+                        <span>{{_("Sign in to our platform")}}</span>
                     </div>
                     <div class="login-dialog-img"></div>
                     <div class="card-body">
                         <form action="{{ url_for('auth.login') }}" class="mt-4" method="POST">
 
                             <div class="form-group">
-                                <label for="email" class="mb-2">Email</label>
+                                <label for="email" class="mb-2">{{ _("Email") }}</label>
                                 <input name="email" id="email" type="email" class="form-control" placeholder="Your email"
                                     required="">
                             </div>
@@ -27,29 +27,24 @@
                             <div class="form-group">
 
                                 <div class="form-group">
-                                    <label for="password" class="mb-2">Password</label>
+                                    <label for="password" class="mb-2">{{ _("Password") }}</label>
                                     <input name="password" id="password" type="password" class="form-control"
                                         placeholder="Your password" required="">
                                 </div>
-
                                 <div class="d-flex justify-content-between align-items-center mb-4">
                                     <div class="form-check">
                                         <label class="form-check-label">
-                                            <input name="remember-me" class="form-check-input" type="checkbox">
-                                            <span class="form-check-x"></span>
-                                            <span class="form-check-sign"></span>
-                                            Remember me
+                                            <!-- Functionality not yet impelemented -->
                                         </label>
                                     </div>
-                                    <p class="m-0"><a href="#" class="text-right">Lost password?</a></p>
                                 </div>
                             </div>
-                            <button type="submit" class="btn btn-block btn-primary">Login</button>
+                            <button type="submit" class="btn btn-block btn-primary">{{ _("Login") }}</button>
                         </form>
                         <div class="d-block d-sm-flex justify-content-center align-items-center mt-4">
                             <p class="font-weight-normal">
-                                Not registered?
-                                <a href="{{ url_for('auth.register') }}" class="font-weight-bold">Create an account</a>
+                                {{_("Not registered?")}}
+                                <a href="{{ url_for('auth.register') }}" class="font-weight-bold">{{ _("Create an account") }}</a>
                             </p>
                         </div>
                     </div>