🚨 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/nginx_https_ingress/handlers/main.yml

@@ -1,6 +1,6 @@
 # Handlers für nginx-https-proxy
 ---
-- name: restart nginx
+- name: Restart nginx
   service:
     name: nginx
     state: restarted

roles/nginx_https_ingress/tasks/main.yml

@@ -56,7 +56,7 @@
     owner: root
     group: root
     mode: '0644'
-  notify: restart nginx
+  notify: Restart nginx
 
 - name: Create directory for dehydrated forwardings
   ansible.builtin.file:
@@ -74,7 +74,7 @@
     group: root
     mode: '0644'
   loop: "{{ ingress }}"
-  notify: restart nginx
+  notify: Restart nginx
 
 - name: Setup nginx configuration
   # Note the order here: The nginx configuration _needs_ he dehydrated-hosts
@@ -86,4 +86,4 @@
     owner: root
     group: root
     mode: '0644'
-  notify: restart nginx
+  notify: Restart nginx