🚨 Fix linter warnings of type 'name[casing]'

ansible-lint reads like this:

    name[casing]: All names should start with an uppercase letter.

While at it: Some task/handler names were slightly adapted to better
match what should be done.

roles/setup_http_site_proxy/tasks/main.yml

@@ -4,10 +4,10 @@
     src: templates/apache-docker-proxy-site.j2
     dest: /etc/apache2/sites-available/{{ site_name }}.conf
     mode: "0644"
-  notify: restart apache2
+  notify: Restart apache2
 
 - name: Activate Apache2 site
   command: a2ensite {{ site_name }}
   args:
     creates: /etc/apache2/sites-enabled/{{ site_name }}.conf
-  notify: restart apache2
+  notify: Restart apache2