refactor(translation): update translation files (#249)

* feat(translation): added Estonian language

* refactor(translation): updated Chinese (Simplified Han script) language

Currently translated at 100.0% (355 of 355 strings)

Translation: OTGateway/Portal
Translate-URL: https://hosted.weblate.org/projects/otgateway/portal/zh_Hans/

* refactor(translation): updated Russian language

Currently translated at 100.0% (355 of 355 strings)

Translation: OTGateway/Portal
Translate-URL: https://hosted.weblate.org/projects/otgateway/portal/ru/

* refactor(translation): updated Dutch language

Currently translated at 100.0% (355 of 355 strings)

Translation: OTGateway/Portal
Translate-URL: https://hosted.weblate.org/projects/otgateway/portal/nl/

* refactor(translation): updated Italian language

Currently translated at 100.0% (355 of 355 strings)

Translation: OTGateway/Portal
Translate-URL: https://hosted.weblate.org/projects/otgateway/portal/it/

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Co-authored-by: Priit Jõerüüt <jrthwlate@users.noreply.hosted.weblate.org>
Co-authored-by: Yurii <34578544+Laxilef@users.noreply.github.com>

src_data/locales/ru.json

@@ -19,7 +19,9 @@
       "rpm": "RPM",
       "ppm": "ppm",
       "byte": "байт",
-      "mbyte": "мбайт"
+      "mbyte": "мбайт",
+      "liter": "Л.",
+      "gallon": "гал."
     },
     "button": {
       "upgrade": "Обновить",