Add highlights for first messages (#3267)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/providers/colors/ColorProvider.cpp

@@ -119,6 +119,20 @@ void ColorProvider::initTypeColorMap()
              std::make_shared<QColor>(
                  HighlightPhrase::FALLBACK_REDEEMED_HIGHLIGHT_COLOR)});
     }
+
+    customColor = getSettings()->firstMessageHighlightColor;
+    if (QColor(customColor).isValid())
+    {
+        this->typeColorMap_.insert({ColorType::FirstMessageHighlight,
+                                    std::make_shared<QColor>(customColor)});
+    }
+    else
+    {
+        this->typeColorMap_.insert(
+            {ColorType::FirstMessageHighlight,
+             std::make_shared<QColor>(
+                 HighlightPhrase::FALLBACK_FIRST_MESSAGE_HIGHLIGHT_COLOR)});
+    }
 }
 
 void ColorProvider::initDefaultColors()

src/providers/colors/ColorProvider.hpp

@@ -11,7 +11,8 @@ enum class ColorType {
     SelfHighlight,
     Subscription,
     Whisper,
-    RedeemedHighlight
+    RedeemedHighlight,
+    FirstMessageHighlight,
 };
 
 class ColorProvider