Gravatar package 3.0

Même s’il fonctionnait très bien en l’état il était nécessaire de moderniser le code du package forxer/gravatar.

Voici le changelog :

• Removed support for PHP prior to 8.0
• Renamed forxer\Gravatar\ namespace to Gravatar\
• Renamed getUrl(string $email) to url() ; email should be defined before
• Introduced gravatar() and gravatar_profile() helpers functions
• Split code into traits to facilitate reading and maintenance
• Used more type hinting for consistency
• Renamed most variables to facilitate reading