JDF compliance on error example

Put the "errors" example in compliance with JDF guidelines and convention found in https://github.com/jboss-jdf/jboss-as-quickstart/blob/master/CONTRIBUTING.md#general-guidelines (Except for the BOM part that'll come in a second time).
For "errors" example it is mainly:

* renaming packages to org.jboss.quickstarts.fuse.errors
* reformatting code to follow JBoss code style
* moving example data to src/main/resources folder
* optimizing pom to meet all JDF guidelines (except BOM requirement)
* running JDF qstools (https://github.com/jboss-jdf/qstools) to validate compliance

All was done in a new jdf-migration branch to let Fuse team to check the proposal and give feedback