Check that bee works with PHP 8.4

[yorkshire-pudding]

As Backdrop 1.31.0 introduces support for PHP 8.4, we should test that everything works for that version and update the README if it does.

[yorkshire-pudding]

The tests all pass but there are a couple of deprecations in the error handler that appear within the 'DBCommands' group of tests:

DBCommands
✔ Db export command works
✔ Db import command works
✔ Db drop command works
PHP Deprecated: _bee_error_handler_real(): Implicitly marking parameter $context as nullable is deprecated, the explicit nullable type must be used instead in /app/includes/errors.inc on line 82
PHP Deprecated: Constant E_STRICT is deprecated in /app/includes/errors.inc on line 211
✔ Db query command works

One of the reasons this has taken so long is that it has been a challenge getting the lando testing environment to work with PHP 8.4, primarily due to how the newer PHP image uses newer database command line clients that cause all sorts of issues. See here if you are interested: lando/php#167

In my attempts to find a solution, I have made some draft changes to Bee that should be documented. To start I will create a list here, but may well create individual issues for some of these:

• Lando's PHP images use the MariaDb client tools with symlinks from MySQL named ones to these; newer versions of the MariaDB client deprecate the use of symlinks.
• Newer versions of the mariaDB client tools also seemed to verify the SSL server certificate which caused problems.
• I have made the Lando machine install the MySQL client tools to remove this; for MySQL this will reflect most MySQL server, though I may need to start testing with MariaDB separately, at least for the DB tests.
• For authenticating to the Database, Bee uses a temporary .cnf file and this implementation was stopping defaults for Lando about column-statistics that I tried to set in the Lando machine. Modifying the implementation has fixed this. Database client config on the server is ignored for db commands #464

I will need to modify how Bee calls the database client executables but currently exploring the most reliable and simple way to do this.