Prefer XML format for getting results from Catch2 output

Catch2 supports multiple reporters including XML reporter (the default value is console reporter). XML reporter is preferable because it is more sold and easy to parse. Console output for human may be cosmetically changed for readability.

```
$ ./Catch2_bench --reporter xml | tee output.xml
```

I want to add support for the XML format and encourage to use it rather than console output. Console output support for Catch2 will continue to be supported since it was already released (To change this v2 release is necessary). Parsing logic can be changed by checking first line is `

```

[xml2js](https://github.com/Leonidas-from-XIV/node-xml2js) seems suitable to parse XML easily.