Joomla 4 upgrade

[tdittmann]

First attempt to migrate the component to Joomla 4

[ilhooq]

Hi @tdittmann,

First of all, many thanks for your contribution!

However, I cannot immediately merge your code because there is a conflict with the old Joomla 3 coding standards. They are installed via composer, so I suggest to update the composer.json to use the last version of joomla/coding-standards (2.0-rc4).

Then, the coding standards can be tested using the apache ant tool (See build.xml) with this command:

ant standard

[ilhooq]

Thank you :+1: