update import.dir description (#1996)

describe how the folder structur should look like to import a project

---------

Co-authored-by: Jan Cizmar <cizmar@chlupac.com>

backend/data/src/main/kotlin/io/tolgee/configuration/tolgee/ImportProperties.kt

@@ -10,7 +10,18 @@ import org.springframework.boot.context.properties.ConfigurationProperties
   displayName = "Import"
 )
 class ImportProperties {
-  @DocProperty(description = "File path of the directory where the file to import are located.")
+  @DocProperty(
+    description = "File path of the directory where the files to import are located.\n" +
+      "\n" +
+      ":::info\n" +
+      "Your folder structure should look like:\n" +
+      "importDir\n" +
+      "└─Project # the foler name is the project name\n" +
+      "  └─validation # the foler name is namespace\n" +
+      "    ├─ en.json # the file name is the target language\n" +
+      "    └─ de.json # second project language\n" +
+      ":::\n\n"
+  )
   var dir: String? = null
 
   @DocProperty(