chat: major UI redesign for v3.0.0 (#2396)

Signed-off-by: Adam Treat <treat.adam@gmail.com>
Signed-off-by: Jared Van Bortel <jared@nomic.ai>
Co-authored-by: Jared Van Bortel <jared@nomic.ai>

gpt4all-chat/qml/MyFancyLink.qml

@@ -0,0 +1,44 @@
+import QtCore
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Controls.Basic
+import Qt5Compat.GraphicalEffects
+import mysettings
+
+MyButton {
+    id: fancyLink
+    property alias imageSource: myimage.source
+
+    Image {
+        id: myimage
+        anchors.verticalCenter: parent.verticalCenter
+        anchors.left: parent.left
+        anchors.leftMargin: 12
+        sourceSize: Qt.size(15, 15)
+        mipmap: true
+        visible: false
+    }
+
+    ColorOverlay {
+        anchors.fill: myimage
+        source: myimage
+        color: fancyLink.hovered ? theme.fancyLinkTextHovered : theme.fancyLinkText
+    }
+
+    borderWidth: 0
+    backgroundColor: "transparent"
+    backgroundColorHovered: "transparent"
+    fontPixelBold: true
+    leftPadding: 35
+    rightPadding: 8
+    topPadding: 1
+    bottomPadding: 1
+    textColor: fancyLink.hovered ? theme.fancyLinkTextHovered : theme.fancyLinkText
+    fontPixelSize: theme.fontSizeSmall
+    background: Rectangle {
+        color: "transparent"
+    }
+
+    Accessible.name: qsTr("Fancy link")
+    Accessible.description: qsTr("A stylized link")
+}