Add import/export of chat colors.

app/src/main/java/org/thoughtcrime/securesms/conversation/colors/ChatColors.kt

@@ -125,6 +125,13 @@ class ChatColors(
 
   fun withId(id: Id): ChatColors = ChatColors(id, linearGradient, singleColor)
 
+  fun matchesWithoutId(other: ChatColors): Boolean {
+    if (linearGradient != other.linearGradient) return false
+    if (singleColor != other.singleColor) return false
+
+    return true
+  }
+
   override fun equals(other: Any?): Boolean {
     val otherChatColors: ChatColors = (other as? ChatColors) ?: return false
 

app/src/main/java/org/thoughtcrime/securesms/conversation/colors/ChatColorsPalette.kt

@@ -162,6 +162,9 @@ object ChatColorsPalette {
     @JvmStatic
     val default = ULTRAMARINE
 
+    /*
+     * If updating this list of colors, make sure to update the backup import/export colors as well.
+     */
     val solids = listOf(
       CRIMSON,
       VERMILION,