Add logging configuration. Add --dump option to just print the full configuration.

src/main/java/io/kamax/mxisd/config/LoggingConfig.java

@@ -0,0 +1,33 @@
+package io.kamax.mxisd.config;
+
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class LoggingConfig {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(LoggingConfig.class);
+
+    private String root;
+
+    public String getRoot() {
+        return root;
+    }
+
+    public void setRoot(String root) {
+        this.root = root;
+    }
+
+    public void build() {
+        String systemLevel = System.getProperty("org.slf4j.simpleLogger.log.io.kamax.mxisd");
+        LOGGER.info("Logging config:");
+        if (StringUtils.isNotBlank(systemLevel)) {
+            LOGGER.info("  Logging level set by environment: {}", systemLevel);
+        } else if (StringUtils.isNotBlank(getRoot())) {
+            LOGGER.info("  Logging level set by the configuration: {}", getRoot());
+            System.setProperty("org.slf4j.simpleLogger.log.io.kamax.mxisd", getRoot());
+        } else {
+            LOGGER.info("  Logging level hasn't set, use default");
+        }
+    }
+}