Add PostgreSQL support (#1620)

* Add PostgreSQL support

* Fix code issues and create integration tests

* Fix identation

* Test Postgres data source in postgres integration test

* Relocated the postgres driver

src/main/java/fr/xephi/authme/initialization/DataSourceProvider.java

@@ -7,6 +7,7 @@ import fr.xephi.authme.datasource.DataSource;
 import fr.xephi.authme.datasource.DataSourceType;
 import fr.xephi.authme.datasource.FlatFile;
 import fr.xephi.authme.datasource.MySQL;
+import fr.xephi.authme.datasource.PostgreSqlDataSource;
 import fr.xephi.authme.datasource.SQLite;
 import fr.xephi.authme.datasource.converter.ForceFlatToSqlite;
 import fr.xephi.authme.datasource.mysqlextensions.MySqlExtensionsFactory;
@@ -71,6 +72,9 @@ public class DataSourceProvider implements Provider<DataSource> {
             case MYSQL:
                 dataSource = new MySQL(settings, mySqlExtensionsFactory);
                 break;
+            case POSTGRESQL:
+                dataSource = new PostgreSqlDataSource(settings, mySqlExtensionsFactory);
+                break;
             case SQLITE:
                 dataSource = new SQLite(settings, dataFolder);
                 break;