Initial work on translations / localization

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3841

Most of the preparation for this was done by Suguru Hirahara (https://github.com/luixxiul).
I've merely reorganized/polished the scripts and instructions in the `i18n/` directory.

While translations can happen even now, more work is necessary to

- make the translation flow better (integrating Weblate), etc.

- restore the Github Actions workflows that Suguru Hirahara had already developed to
  adapt them to our new workflow

i18n/locales/jp/LC_MESSAGES/docs/maintenance-checking-services.po

@@ -0,0 +1,54 @@
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) 2018-2024, Slavi Pantaleev, Aine Etke, MDAD community
+# members
+# This file is distributed under the same license as the
+# matrix-docker-ansible-deploy package.
+# FIRST AUTHOR <EMAIL@ADDRESS>, 2024.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: matrix-docker-ansible-deploy \n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2024-12-16 12:05+0900\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language: jp\n"
+"Language-Team: jp <LL@li.org>\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Generated-By: Babel 2.16.0\n"
+
+#: ../../../docs/maintenance-checking-services.md:1
+msgid "Checking if services work"
+msgstr ""
+
+#: ../../../docs/maintenance-checking-services.md:3
+msgid ""
+"This playbook can perform a check to ensure that you've configured things"
+" correctly and that services are running."
+msgstr ""
+
+#: ../../../docs/maintenance-checking-services.md:5
+msgid "To perform the check, run:"
+msgstr ""
+
+#: ../../../docs/maintenance-checking-services.md:11
+msgid ""
+"The shortcut command with `just` program is also available: `just run-"
+"tags self-check`"
+msgstr ""
+
+#: ../../../docs/maintenance-checking-services.md:13
+msgid "If it's all green, everything is probably running correctly."
+msgstr ""
+
+#: ../../../docs/maintenance-checking-services.md:15
+msgid ""
+"Besides this self-check, you can also check whether your server federates"
+" with the Matrix network by using the [Federation "
+"Tester](https://federationtester.matrix.org/) against your base domain "
+"(`example.com`), not the `matrix.example.com` subdomain."
+msgstr ""
+