Fix security and setup warnings

Update PHP configuration

#Switch the following directory to change the php memory limit 
cd /etc/php/7.4/apache2/

#Edit the php.ini file
sudo nano php.ini

#After that restart the service apache2 
sudo service apache2 restart 

No default phone region is set and no memory cache has been configured

#Switch to the following directory to enable caching and set your phone-region
cd /var/www/nextcloud/config

#Edit the config.php file
sudo nano config.php

Further Nextcloud configuration

#Switch to the following directory to make some furthermore changes
cd /var/www/nextcloud

#Update .htaccess
sudo -u www-data php occ maintenance:update:htaccess

#Switch to the following directory to make some furthermore changes
cd /etc/apache2/sites-vailable

#Edit the 000-default.conf file
sudo nano 000-default.conf

#Paste the following code into the file (take a look at the picture below)
RewriteEngine On
RewriteRule ^/\.well-known/carddav https://%{SERVER_NAME}/remote.php/dav/ [R=301,L]
RewriteRule ^/\.well-known/caldav https://%{SERVER_NAME}/remote.php/dav/ [R=301,L]
RewriteRule ^/\.well-known/host-meta https://%{SERVER_NAME}/public.php?service=host-meta [QSA,L]
RewriteRule ^/\.well-known/host-meta\.json https://%{SERVER_NAME}/public.php?service=host-meta-json [QSA,L]
RewriteRule ^/\.well-known/webfinger https://%{SERVER_NAME}/public.php?service=webfinger [QSA,L] 

#Tell the system to rewrite a2enmod
sudo a2enmod rewrite

#Restart the apache2 service 
sudo service apache2 restart

Fix php-imagick warning

#Uninstall all packages from imagemagick
sudo apt remove imagemagick-6-common

#Remove php-imagick
sudo apt remove php-imagick 

#Remove non-used packages
sudo apt autoremove

#Install php-imagick and imagemagick
sudo apt install php-imagick imagemagick

#Restart the apache2 service 
sudo service apache2 restart

Now there are no warnings anymore!