[v4] New translations root

[afbora]

This PR …

This is K4 version of #6212. Doesn't include a breaking change.

Fixes

• External language variables setup no longer works since K4's language views External language variables setup no longer works since K4's language views #6176

Features

• New translations root

$kirby = new Kirby([
    'roots' => [
        'translations' => __DIR__ . '/site/translations',
    ],
]);

Breaking changes

None

Ready?

• Unit tests for fixed bug/feature
• In-code documentation (wherever needed)
• Tests and checks all pass

For review team

• Add changes to release notes draft in Notion
• Add to website docs release checklist (if needed)

[bastianallgeier]

Wouldn't it make sense to even unset it here?

[afbora]

Seems setting empty array is correct.

With set empty array:

<?php

return [
    'code' => 'en',
    'default' => true,
    'direction' => 'ltr',
    'locale' => [
        'LC_ALL' => 'en_US'
    ],
    'name' => 'EN',
    'translations' => [

    ],
    'url' => NULL
];

With unseting:

<?php

return [
    'code' => 'en',
    'default' => true,
    'direction' => 'ltr',
    'locale' => [
        'LC_ALL' => 'en_US'
    ],
    'name' => 'EN',
    'url' => NULL
];

[afbora]

I didn't understand the unit test coverage.

For ex: I added LanguageTranslations::get tests with @covers notation but shows still uncovered.

Changes:
https://github.com/getkirby/kirby/pull/6216/files#diff-4e3a14d5dc988b6b8165c6ab49bbe0a32cf21c4c141054da017fe0730e83bf5aR54-R82

Codecov:
https://app.codecov.io/gh/getkirby/kirby/pull/6216/blob/src/Cms/LanguageTranslations.php#L34

[distantnative]

@lukasbestle @afbora To be honest, I find the v4 version very confusing with the duality of the translation prop and translationObject etc. Since this is an area already hard to overlook and understand (even just with all the language, translation etc. names that are so similar), I would vote for letting go of a v4 version but really just focus on finishing the v5 version (which looks so much nicer already due to the cleaner syntax).