feat(17-04): faq:import-winter and the read-only Winter export SQL

- JSON lines import keeping ids, locale_id looked up by locale code (an unknown code aborts before any write)
- one transaction, setval past the copied ids, --force replaces, --dry-run reports, an empty file copies nothing
- scripts/winter-export.sql: SELECT JSON_OBJECT with the translate locale code
- TestFaqImportSmoke

scripts/winter-export.sql

@@ -0,0 +1,39 @@
+-- FAQs of a WinterCMS site with the Golem15.FAQ plugin, one JSON object per
+-- line: the --file input of faq:import-winter.
+--
+--   mysql -N -B --raw <database> < winter-export.sql > faqs.jsonl
+--
+-- Read-only: it selects from the FAQ table and the translate locales table
+-- and changes nothing. JSON_OBJECT needs MySQL 5.7.8+ or MariaDB 10.2.3+.
+--
+-- Check two names on the server before running:
+--
+-- 1. The FAQ table. This file assumes golem15_faq_faqs:
+--      SHOW TABLES LIKE '%faq_faqs';
+--
+-- 2. The translate locales table that locale_id points at. This file
+--    assumes golem15_translate_locales (Golem15.Translate). Check:
+--      SHOW TABLES LIKE '%translate_locales';
+--    A site on Winter.Translate or RainLab.Translate uses
+--    winter_translate_locales or rainlab_translate_locales; change the JOIN
+--    line to match.
+--
+-- locale_code is the locale's code: the command looks the code up among the
+-- application's translate locales, so the ids may differ between the sites.
+-- Every code must exist there before the import (an unknown code aborts it).
+-- content is the stored question and answer list as text; the command
+-- decodes it.
+SELECT JSON_OBJECT(
+    'id', f.id,
+    'name', f.name,
+    'slug', f.slug,
+    'locale_code', l.code,
+    'is_active', f.is_active,
+    'description', f.description,
+    'content', f.content,
+    'created_at', f.created_at,
+    'updated_at', f.updated_at
+)
+FROM golem15_faq_faqs f
+LEFT JOIN golem15_translate_locales l ON l.id = f.locale_id
+ORDER BY f.id;