Translations update from Hosted Weblate (#594)

* Translated using Weblate (Thai)

Currently translated at 71.1% (387 of 544 strings)

Co-authored-by: Nayuki <me@nayuki.cyou>
Translate-URL: https://hosted.weblate.org/projects/kotatsu/strings/th/
Translation: Kotatsu/Strings

* Translated using Weblate (Spanish)

Currently translated at 100.0% (546 of 546 strings)

Co-authored-by: gallegonovato <fran-carro@hotmail.es>
Translate-URL: https://hosted.weblate.org/projects/kotatsu/strings/es/
Translation: Kotatsu/Strings

* Translated using Weblate (Turkish)

Currently translated at 100.0% (546 of 546 strings)

Co-authored-by: Oğuz Ersen <oguz@ersen.moe>
Translate-URL: https://hosted.weblate.org/projects/kotatsu/strings/tr/
Translation: Kotatsu/Strings

* Translated using Weblate (Russian)

Currently translated at 99.8% (545 of 546 strings)

Co-authored-by: Hotarun <ihotarun@proton.me>
Translate-URL: https://hosted.weblate.org/projects/kotatsu/strings/ru/
Translation: Kotatsu/Strings

---------

Co-authored-by: Nayuki <me@nayuki.cyou>
Co-authored-by: gallegonovato <fran-carro@hotmail.es>
Co-authored-by: Oğuz Ersen <oguz@ersen.moe>
Co-authored-by: Hotarun <ihotarun@proton.me>

app/src/main/res/values-es/strings.xml

@@ -539,4 +539,8 @@
     <string name="error_filter_locale_genre_not_supported">Esta fuente no permite filtrar por géneros ni por configuración regional</string>
     <string name="genres_search_hint">Empieza a escribir el nombre del género</string>
     <string name="disable_battery_optimization_summary_downloads">Puede que te ayude a iniciar la descarga si tienes algún problema</string>
+    <string name="welcome_text">Por favor, seleccione las fuentes de contenido que desea habilitar. Esto también se puede configurar más tarde en la configuración</string>
+    <string name="restore">Restaurar</string>
+    <string name="backup_date_">Fecha de la copia de seguridad: %s</string>
+    <string name="sync_auth">Iniciar sesión en la cuenta de sincronización</string>
 </resources>