Add native XML Formatter

We have a zero dependency 100% Java XML formatter here which respects the same configuration options as `prettier` but does not require `npm` and dealing with npm install especially in firewalled clients.

- Formatter.format - https://github.com/jbrower2/xml-formatter/blob/main/src/main/java/com/jeffbrower/Formatter.java

- Checker.check - https://github.com/jbrower2/xml-formatter/blob/main/src/main/java/com/jeffbrower/Checker.java

We think this would be a great native XML formatter as we use Java Server Faces are are using this to format our XHTML pages across projects in a standard format.

@nedtwigg do you think this would be acceptable to donate?

@blutorange i may ask for your help 😄