Use custom QueryPagingSource (#7321)

* Use custom QueryPagingSource

- Adds placeholder to make the list jump around less
- Fixes issue where SQLDelight QueryPagingSource would throw IndexOutOfBounds

* Review Changes

app/src/main/java/eu/kanade/presentation/util/Shimmer.kt

@@ -0,0 +1,9 @@
+package eu.kanade.presentation.util
+
+import androidx.compose.ui.graphics.Color
+
+val shimmerGradient = listOf(
+    Color.LightGray.copy(alpha = 0.8f),
+    Color.LightGray.copy(alpha = 0.2f),
+    Color.LightGray.copy(alpha = 0.8f),
+)