Make the default config sources more robust when a security manager is installed

If we don't have permission to access system properties or the environment then fall back to defaults.

Author: mcculls

internal-api/src/main/java/datadog/trace/bootstrap/config/provider/EnvironmentConfigSource.java

@@ -8,7 +8,11 @@ final class EnvironmentConfigSource extends ConfigProvider.Source {
 
   @Override
   protected String get(String key) {
-    return System.getenv(propertyNameToEnvironmentVariableName(key));
+    try {
+      return System.getenv(propertyNameToEnvironmentVariableName(key));
+    } catch (SecurityException e) {
+      return null;
+    }
   }
 
   @Override

internal-api/src/main/java/datadog/trace/bootstrap/config/provider/SystemPropertiesConfigSource.java

@@ -8,7 +8,11 @@ public final class SystemPropertiesConfigSource extends ConfigProvider.Source {
 
   @Override
   protected String get(String key) {
-    return System.getProperty(propertyNameToSystemPropertyName(key));
+    try {
+      return System.getProperty(propertyNameToSystemPropertyName(key));
+    } catch (SecurityException e) {
+      return null;
+    }
   }
 
   @Override