Add language: Welsh (#7866)

* Create messages.po

* Update app.config.js

* Update lingui.config.js

* Update dates.ts

* Update helpers.ts

* Update i18n.ts

* Update i18n.web.ts

* Update languages.ts

src/locale/locales/cy/messages.po

@@ -0,0 +1,13 @@
+msgid ""
+msgstr ""
+"POT-Creation-Date: 2023-11-05 16:01-0800\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"X-Generator: @lingui/cli\n"
+"Language: cy\n"
+"Project-Id-Version: bluesky-social\n"
+"Report-Msgid-Bugs-To: \n"
+"PO-Revision-Date: \n"
+"Last-Translator: \n"
+"Language-Team: Welsh\n"