app: switch from kotlinx to square

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

app/proguard-rules.pro

@@ -1,14 +1 @@
 -keepattributes *Annotation*, EnclosingMethod, InnerClasses
--dontnote kotlinx.serialization.AnnotationsKt # core serialization annotations
-
--keep,includedescriptorclasses class dev.msfjarvis.lobsters.model.**$$serializer { *; }
--keepclassmembers class dev.msfjarvis.lobsters.model.** {
-    *** Companion;
-}
--keepclasseswithmembers class dev.msfjarvis.lobsters.model.** {
-    kotlinx.serialization.KSerializer serializer(...);
-}
-
-# Inline-based optimizations cause reflection to fail within Ktor (from what I can tell), so we turn
-# this off for now.
--dontoptimize

app/src/main/java/dev/msfjarvis/lobsters/data/source/LobstersApiTypeConverters.kt

@@ -1,24 +1,25 @@
 package dev.msfjarvis.lobsters.data.source
 
 import androidx.room.TypeConverter
+import com.squareup.moshi.Moshi
 import dev.msfjarvis.lobsters.model.Submitter
-import kotlinx.serialization.decodeFromString
+import dev.msfjarvis.lobsters.model.SubmitterJsonAdapter
-import kotlinx.serialization.encodeToString
-import kotlinx.serialization.json.Json
 
 object LobstersApiTypeConverters {
   private const val SEPARATOR = ","
+  private val moshi = Moshi.Builder().build()
+  private val submitterAdapter = SubmitterJsonAdapter(moshi)
 
   @TypeConverter
   @JvmStatic
   fun toSubmitterUser(value: String?): Submitter? {
-    return value?.let { Json.decodeFromString(value) }
+    return value?.let { submitterAdapter.fromJson(value) }
   }
 
   @TypeConverter
   @JvmStatic
   fun fromSubmitterUser(value: Submitter?): String? {
-    return value?.let { Json.encodeToString(value) }
+    return submitterAdapter.toJson(value)
   }
 
   @TypeConverter