BREAKING CHANGE(core): Implement custom XmlBuilder, remove xmlbuilder2, upgrade fast-xml-parser, update SmartXml API, tests and CI

ts/smartxml.plugins.ts

@@ -1,7 +1,3 @@
 import * as fastXmlParser from 'fast-xml-parser';
-import * as xmlbuilder2 from 'xmlbuilder2';
 
-export {
-  fastXmlParser,
-  xmlbuilder2,
-};
+export { fastXmlParser };