feat: allow TimestampElement to have extra flags

This allows you to create TimestampElements that have additional flags,
     such as an extra "Header" flag

src/messages/MessageElement.cpp

@@ -1330,6 +1330,24 @@ TimestampElement::TimestampElement(QTime time)
     assert(this->element_ != nullptr);
 }
 
+TimestampElement::TimestampElement(QTime time,
+                                   const MessageElementFlags extraFlags)
+    : MessageElement(extraFlags | MessageElementFlag::Timestamp)
+    , time_(time)
+    , element_(this->formatTime(time))
+{
+    assert(this->element_ != nullptr);
+}
+
+TimestampElement::TimestampElement(TimestampElement::CloneConstructorTag,
+                                   QTime time, const MessageElementFlags flags)
+    : MessageElement(flags)
+    , time_(time)
+    , element_(this->formatTime(time))
+{
+    assert(this->element_ != nullptr);
+}
+
 void TimestampElement::addToContainer(MessageLayoutContainer &container,
                                       const MessageLayoutContext &ctx)
 {
@@ -1352,9 +1370,8 @@ TextElement *TimestampElement::formatTime(const QTime &time)
 
     QString format = locale.toString(time, getSettings()->timestampFormat);
 
-    auto *text =
-        new TextElement(format, MessageElementFlag::Timestamp,
-                        MessageColor::System, FontStyle::TimestampMedium);
+    auto *text = new TextElement(format, this->getFlags(), MessageColor::System,
+                                 FontStyle::TimestampMedium);
     text->setLink(this->getLink());
     text->setTooltip(this->getTooltip());
     return text;
@@ -1385,7 +1402,8 @@ std::string_view TimestampElement::type() const
 
 std::unique_ptr<MessageElement> TimestampElement::clone() const
 {
-    auto elem = std::make_unique<TimestampElement>(this->time_);
+    auto elem = std::make_unique<TimestampElement>(
+        TimestampElement::CloneConstructorTag{}, this->time_, this->getFlags());
     elem->cloneFrom(*this);
     return elem;
 }

src/messages/MessageElement.hpp

@@ -667,11 +667,19 @@ protected:
 // contains a text, formated depending on the preferences
 class TimestampElement : public MessageElement
 {
+protected:
+    struct CloneConstructorTag {
+    };
+
 public:
     static constexpr std::string_view TYPE = "timestamp";
 
     TimestampElement();
     TimestampElement(QTime time_);
+    TimestampElement(QTime time_, MessageElementFlags extraFlags);
+    /// This is intended only for cloning the element.
+    TimestampElement(TimestampElement::CloneConstructorTag, QTime time_,
+                     MessageElementFlags flags);
     ~TimestampElement() override = default;
 
     void addToContainer(MessageLayoutContainer &container,