App type-based configs

[brandonkelly]

Adds support for app type-based configs, for general and db (e.g. general.web.php/general.console.php).

In addition to returning an array or new GeneralConfig/DbConfig object, general and db config files can now return a callable which accepts an existing config object, so it’s possible for app type-based configs to use the fluent syntax on the same config object created by the original config file (general.php/db.php):

// config/general.php

return GeneralConfig::create()
    ->aliases([
        '@webroot' => dirname(__DIR__) . '/web',
    ])
    // ...
;

// or

return fn(GeneralConfig $config) => $config
    ->aliases([
        '@webroot' => dirname(__DIR__) . '/web',
    ])
    // ...
;

// config/general.console.php

return fn(GeneralConfig $config) => $config
    ->addAlias('@web', craft\helpers\App::env('CLI_WEB_URL'))
    // ...
;

[linear]

CMS-1312 App type-based configs

[timkelty]

LGTM

Related thought: we could provide some if methods for fluent config to facilitate the same kind of thing but in a single file. Could also be handy for environment conditions, eg:

<?php
return GeneralConfig::create()
    ->if(
        true, // expression
        fn(GeneralConfig $config) => $config->devMode(true), // if
        fn(GeneralConfig $config) => $config->devMode(false), // else
    )
    ->ifEnvironment(
        'dev', // CRAFT_ENVIRONMENT=dev
        fn(GeneralConfig $config) => $config->devMode(true)
    )
    ->ifWeb(fn(GeneralConfig $config) => $config->('@web', 'https://example.com'))
    ->ifConsole(fn(GeneralConfig $config) => $config->addAlias('@webroot', '/var/www/html'));