Rename moodle ini to support easier lexical sorting

[andrewnicols]

With the new entrypoint conf.d support, we want to be able to easily support prioritisation of the various ini options.

Numerically prefixed ini files are easier to lexically order.

Typically we want the standard file to be at the beginning because it's a staple which others should be able to override in most cases, but we also want to allow people to apply earlier files too.

As it stands, the current name (docker-php-moodle.ini) will be called after any numerically-prefixed ini file due to the standard lexical sort.

[stronk7]

Thanks, merged. Will backport this together with other stuff to >= php74

[stronk7]

Done: Backported to >= php74.