fea: allow use of system proxy (#652)

Author: aallam

src/main/scala/algolia/AlgoliaClientConfiguration.scala

@@ -31,7 +31,8 @@ case class AlgoliaClientConfiguration(
     httpReadTimeoutMs: Int,
     httpRequestTimeoutMs: Int,
     dnsTimeoutMs: Int,
-    hostDownTimeoutMs: Int
+    hostDownTimeoutMs: Int,
+    useSystemProxy: Boolean = false
 ) {}
 
 object AlgoliaClientConfiguration {

src/main/scala/algolia/AlgoliaHttpClient.scala

@@ -49,6 +49,7 @@ case class AlgoliaHttpClient(
       .setConnectTimeout(configuration.httpConnectTimeoutMs)
       .setReadTimeout(configuration.httpReadTimeoutMs)
       .setRequestTimeout(configuration.httpRequestTimeoutMs)
+      .setUseProxyProperties(configuration.useSystemProxy)
       .build
 
   val dnsNameResolver: DnsNameResolver =