Move dynamic segments from Premium plugin

[MAILPOET-2382]

lib/DynamicSegments/Exceptions/ErrorSavingException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace MailPoet\Premium\DynamicSegments\Exceptions;
+
+class ErrorSavingException extends \Exception {
+
+}

lib/DynamicSegments/Exceptions/InvalidSegmentTypeException.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace MailPoet\Premium\DynamicSegments\Exceptions;
+
+class InvalidSegmentTypeException extends \Exception {
+
+  const MISSING_TYPE = 1;
+  const INVALID_TYPE = 2;
+  const MISSING_ROLE = 3;
+  const MISSING_ACTION = 4;
+  const MISSING_NEWSLETTER_ID = 5;
+  const MISSING_CATEGORY_ID = 6;
+  const MISSING_PRODUCT_ID = 7;
+
+};