Prometheus - Donation and payment store

1. Timezone is no longer defaulted to Europe/Berlin. It now respects php.ini unless $timezone is set in the config file.
2. PHP 8.0 support.
3. MySQL 8.0 support.
4. I finally managed to spell 'successful' correctly in the successful installation message.
5. Fixed labels display in packages.
6. Fixed gifting packages using credits.
7. Swapped out the Steam login image with the one Steam recommends you use.
8. Submit buttons are now a green success colour to distinguish them from other actions.
9. Fix payments using Stripe on newer versions of the Stripe webhook API.

Modified files

Web

1. admin.php
2. admin/pkg.php
3. admin/pkg/php.php
4. compiled/*
5. config.example.php
6. inc/classes/gateways.class.php
7. inc/classes/packages.class.php
8. inc/classes/prometheus.class.php
9. inc/classes/steamLogin.class.php
10. inc/credits.php
11. inc/functions.php
12. inc/header.php
13. index.php
14. logout.php
15. pages/admin/users/credits.php
16. profile.php
17. store.php
18. vendor/*
19. stripe.php