Multiple minors fix and improve

use data class for entity
Add sealed on entity interfaces
Replace listOf() by setOf() instead of deduplicate
use interface instead of EntityRef
replace .toLowerCase() to .lowercase()
fix test.sh

src/main/kotlin/fr/dcproject/component/article/routes/UpsertArticle.kt

@@ -37,7 +37,7 @@ object UpsertArticle {
             val anonymous: Boolean = true,
             val content: String,
             val description: String,
-            val tags: List<String> = emptyList(),
+            val tags: Set<String> = emptySet(),
             val draft: Boolean = false,
             val versionId: UUID,
             val workgroup: WorkgroupRef? = null,