Create SQL data source utils class

- Extract logic used in SQLite and MySQL for logging and closing SQL objects
    - Decided to leave buildAuthFromResultSet methods individually as this might be more implementation-specific
- Rename DataSource#close to DataSource#closeConnection to fix conflict with static import

src/main/java/fr/xephi/authme/datasource/SQLite.java

@@ -21,6 +21,9 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import static fr.xephi.authme.datasource.SqlDataSourceUtils.close;
+import static fr.xephi.authme.datasource.SqlDataSourceUtils.logSqlException;
+
 /**
  */
 public class SQLite implements DataSource {
@@ -60,10 +63,6 @@ public class SQLite implements DataSource {
         this.con = connection;
     }
 
-    private static void logSqlException(SQLException e) {
-        ConsoleLogger.logException("Error while executing SQL statement:", e);
-    }
-
     private void connect() throws ClassNotFoundException, SQLException {
         Class.forName("org.sqlite.JDBC");
         ConsoleLogger.info("SQLite driver loaded");
@@ -384,7 +383,7 @@ public class SQLite implements DataSource {
     }
 
     @Override
-    public void close() {
+    public void closeConnection() {
         try {
             if (con != null && !con.isClosed()) {
                 con.close();
@@ -394,36 +393,6 @@ public class SQLite implements DataSource {
         }
     }
 
-    private static void close(Statement st) {
-        if (st != null) {
-            try {
-                st.close();
-            } catch (SQLException ex) {
-                logSqlException(ex);
-            }
-        }
-    }
-
-    private static void close(Connection con) {
-        if (con != null) {
-            try {
-                con.close();
-            } catch (SQLException ex) {
-                logSqlException(ex);
-            }
-        }
-    }
-
-    private static void close(ResultSet rs) {
-        if (rs != null) {
-            try {
-                rs.close();
-            } catch (SQLException ex) {
-                logSqlException(ex);
-            }
-        }
-    }
-
     @Override
     public List<String> getAllAuthsByIp(String ip) {
         PreparedStatement pst = null;