Add support for Xdebug 3

[valenvb]

This addresses #61, updating the configuration to support xdebug 3. It also contains a couple of fixes I encountered on the way to resolving this, namely using host.docker.internal if resolvable as the Xdebug client address, and splitting configuration into web and cli components to avoid filling the CLI with messages if the debugger is off while using buildkit and other php commands.