Moved `Piwik\Translate\Writer` and its subclasses to the LanguagesManager plugin

plugins/LanguagesManager/Commands/FetchFromOTrance.php

plugins/LanguagesManager/Commands/SetTranslations.php

plugins/LanguagesManager/Commands/Update.php

...anguagesManager/Test/Integration/LanguagesManagerTest.php

.../Unit/TranslationWriter/Filter/ByBaseTranslationsTest.php

...st/Unit/TranslationWriter/Filter/ByParameterCountTest.php

...t/Unit/TranslationWriter/Filter/EmptyTranslationsTest.php

...est/Unit/TranslationWriter/Filter/EncodedEntitiesTest.php

...t/TranslationWriter/Filter/UnnecassaryWhitespacesTest.php

.../Unit/TranslationWriter/Validate/CoreTranslationsTest.php

...er/Test/Unit/TranslationWriter/Validate/NoScriptsTest.php

...nguagesManager/Test/Unit/TranslationWriter/WriterTest.php

...esManager/TranslationWriter/Filter/ByBaseTranslations.php

...agesManager/TranslationWriter/Filter/ByParameterCount.php

...gesManager/TranslationWriter/Filter/EmptyTranslations.php

...uagesManager/TranslationWriter/Filter/EncodedEntities.php

...guagesManager/TranslationWriter/Filter/FilterAbstract.php

...nager/TranslationWriter/Filter/UnnecassaryWhitespaces.php

...esManager/TranslationWriter/Validate/CoreTranslations.php

...LanguagesManager/TranslationWriter/Validate/NoScripts.php