refactor: migrate to kotlinx serialization, eliminate gson dependency

app/src/main/java/com/bitcointxoko/gudariwallet/api/NodeAliasClient.kt.kt

@@ -1,8 +1,9 @@
 package com.bitcointxoko.gudariwallet.api
 
+import okhttp3.MediaType.Companion.toMediaType
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
-import retrofit2.converter.gson.GsonConverterFactory
+import retrofit2.converter.kotlinx.serialization.asConverterFactory
 import java.util.concurrent.TimeUnit
 
 /**
@@ -17,17 +18,20 @@ class NodeAliasClient {
         .readTimeout(5, TimeUnit.SECONDS)
         .build()
 
+    private val converter = JsonProvider.json
+        .asConverterFactory("application/json; charset=UTF-8".toMediaType())
+
     private val mempoolApi: MempoolApi = Retrofit.Builder()
         .baseUrl("https://mempool.space/")
         .client(client)
-        .addConverterFactory(GsonConverterFactory.create())
+        .addConverterFactory(converter)
         .build()
         .create(MempoolApi::class.java)
 
     private val oneMlApi: OneMlApi = Retrofit.Builder()
         .baseUrl("https://1ml.com/")
         .client(client)
-        .addConverterFactory(GsonConverterFactory.create())
+        .addConverterFactory(converter)
         .build()
         .create(OneMlApi::class.java)