Merge branch '7359-update-php83' into 'master'

.gitignore

config/config_custom.php.dist

config/inc_projects_config.php

config/lang/de-de.json

config/lang/en-en.json

docker/.env

docker/containers/web-server/Dockerfile

...containers/web-server/apache/sites-enabled/vhost_app.conf

docker/containers/web-server/php/extra-php-config.ini

docker/docker-compose.yml

docker/init.sh

docs/10_Get_started/20_Installation_with_Docker.md

docs/10_Get_started/30_Filestructure.md

hooks/templates/config_custom.php.erb

public_html/api/index.php

public_html/appmonitor/general_include.php

public_html/appmonitor/git_update_appmonitor.sh

public_html/appmonitor/index.php

...ic_html/appmonitor/plugins/apps/iml-appmonitor-server.php

public_html/appmonitor/plugins/apps/inc_appcheck_end.php