- Добавил возможность редактирования сообщений

- Улучшил внешний вид страниц.

https://www.youtube.com/watch?v=-gdDklUu03k&list=PLU2ftbIeotGpAYRP9Iv2KLIwK36-o_qYk&index=20

src/main/resources/templates/parts/messageEditor.ftl

@@ -0,0 +1,39 @@
+<a class="btn btn-primary mb-3" data-toggle="collapse" href="#collapseExample" role="button" aria-expanded="false"
+   aria-controls="collapseExample">
+    Message editor
+</a>
+<div class="collapse <#if message??>show</#if>" id="collapseExample">
+    <div class="form-group mt-3">
+        <form method="post" enctype="multipart/form-data">
+            <div class="form-group">
+                <input type="text" class="form-control ${(textError??)?string('is-invalid', '')}"
+                       value="<#if message??>${message.text}</#if>" name="text" placeholder="Text"/>
+                <#if textError??>
+                    <div class="invalid-feedback">
+                        ${textError}
+                    </div>
+                </#if>
+            </div>
+            <div class="form-group">
+                <input type="text" class="form-control ${(tagError??)?string('is-invalid', '')}"
+                       value="<#if message??>${message.tag}</#if>" name="tag" placeholder="Tag">
+                <#if tagError??>
+                    <div class="invalid-feedback">
+                        ${tagError}
+                    </div>
+                </#if>
+            </div>
+            <div class="form-group">
+                <div class="custom-file">
+                    <input type="file" name="file" id="customFile">
+                    <label class="custom-file-label" for="customFile">Choose file</label>
+                </div>
+            </div>
+            <input type="hidden" name="_csrf" value="${_csrf.token}"/>
+            <input type="hidden" name="message-id" value=<#if message??>${message.id}</#if>/>
+            <div class="form-group">
+                <button type="submit" class="btn btn-primary">Save message</button>
+            </div>
+        </form>
+    </div>
+</div>