feat: Extract translation text from html and finished the mainly translation of zh_CN, zh_TW, ja_JP file (#987)

* feat: translate zh_cn properties

* feat: adjust some description messages_zh_CN.properties

* feat: translate zh_TW file done

* feat: zh_CN semantic optimization

* feat: Supplementary ja_JP translation

* feat: extract rest text

* feat: Sync to all lang.properties

* feat: translate zh_CN, zh_TW, ja_JP file

* fix: small bug

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Co-authored-by: yanyu_lin <yanyu_lin@bestsign.cn>

src/main/resources/templates/misc/add-image.html

@@ -88,7 +88,7 @@
 
               <!-- download button -->
               <div class="margin-auto-parent">
-                <button id="download-pdf" class="btn btn-primary mb-2 show-on-file-selected margin-center">Download PDF</button>
+                <button id="download-pdf" class="btn btn-primary mb-2 show-on-file-selected margin-center" th:text="#{downloadPdf}"></button>
               </div>
               <script>
                 document.getElementById("download-pdf").addEventListener('click', async() => {