Feature/drop support for php 7. Modernizations

[Chris53897]

I am aware that most users are still on 7.4.
But i guess (hope) version 6 of this bundle is useing php >= 8.

There are BC breaks because of the typehints. That is the reason i suggest version 6 for this PR.

• drop-support-for-php-7
• add php8 feature
• add strong php 8 typehints
• remove MapzenFactory and GeoIPsFactory
• migrate phpunit.xml.dist to phununit 9 format
• fixed some spelling mistake

WDYT?

P.S: If someone has a solution for phpstan-warning, please let me know.

[norkunas]

Sorry, but it's too hard to review so many changes in a single PR, so I'd prefer splitting features.
And since we need to align with Symfony maintained versions, we won't currently change php requirements

[Chris53897]

That is understandable.

Most features depend on php 8. Others could be split now, or after dropping the support of php 7.
I will split some tasks.

Are there any plans for version 6?
With 5.x php 7.3 ist still supported to align with symfony.
But i can understand the maintenance overhead.