Show only the "Other locales" feedback from relevant languages

[amieiro]

What problem does this address?

Following what we did in Improving Translation Suggestions from Other Languages, there is another improvement: only show the relevant languages for the current locale, removing the other ones from the list.

Proposed by @fxbenard here.

What is your proposed solution?

Add a new array:

public array $relevant_locales = array(
        'gl' => array( 'es', 'pt', 'pt-ao', 'pt-br', 'ca', 'it', 'fr', 'ro' ),
        'es' => array( 'es-ve', 'gl', 'ca', 'pt', 'pt-ao', 'pt-br', 'it', 'fr', 'ro' ),
    );

If the language is in this array, it will be in the "Other locales" feedback. If we don't have any key for the current language, it will return all the languages in the "Other locales" feedback.

This will remove the variants if they are not in the array: e.g., for the Galician language, it won't show the Spanish variants and for the Spanish (Spain), it will only show the Spanish (Venezuela) variant.