Implement initial authentication flow

app/src/main/java/gq/kirmanak/mealie/data/RetrofitBuilder.kt

@@ -0,0 +1,20 @@
+package gq.kirmanak.mealie.data
+
+import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.json.Json
+import okhttp3.MediaType
+import retrofit2.Retrofit
+import javax.inject.Inject
+
+@ExperimentalSerializationApi
+class RetrofitBuilder @Inject constructor() {
+    fun buildRetrofit(baseUrl: String): Retrofit {
+        val url = if (baseUrl.startsWith("http")) baseUrl else "https://$baseUrl"
+        val contentType = MediaType.get("application/json")
+        return Retrofit.Builder()
+            .baseUrl(url)
+            .addConverterFactory(Json.asConverterFactory(contentType))
+            .build()
+    }
+}