Add preference to align attributes to tag vs simply indent them

[fbricon]

Following up on #100, currently when attributes are formatted 1 per line, they're aligned on the tag. Which can be fine in some case, but not to the taste of everybody. There should be a preference that allows to simply indent them instead (default Eclipse behaviour).
So for instance, with "xml.format.alignAttributesWithTag": true :

<xsl:stylesheet
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               xmlns:xs="http://www.w3.org/2001/XMLSchema"
               xmlns:math="http://www.w3.org/2005/xpath-functions/math"
               xmlns:xd="http://www.oxygenxml.com/ns/doc/xsl"
               xmlns:emp="http://www.semanticalllc.com/ns/employees#"
               xmlns:h="http://www.w3.org/1999/xhtml"
               xmlns:fn="http://www.w3.org/2005/xpath-functions"
               xmlns:j="http://www.w3.org/2005/xpath-functions"
               exclude-result-prefixes="xs math xd h emp"
               version="2.0">

and with "xml.format.alignAttributesWithTag": false

<xsl:stylesheet
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:math="http://www.w3.org/2005/xpath-functions/math"
    xmlns:xd="http://www.oxygenxml.com/ns/doc/xsl"
    xmlns:emp="http://www.semanticalllc.com/ns/employees#"
    xmlns:h="http://www.w3.org/1999/xhtml"
    xmlns:fn="http://www.w3.org/2005/xpath-functions"
    xmlns:j="http://www.w3.org/2005/xpath-functions"
    exclude-result-prefixes="xs math xd h emp" version="2.0">

I now think such preference should be set to false.

[NikolasKomonen]

@fbricon

Does this look fine after a format:

<?xml version="1.0" encoding="UTF-8"?>
<project
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.eclipse</groupId>
  <artifactId>lsp4xml</artifactId>
  <version>0.0.2-SNAPSHOT</version>
  <packaging></packaging>
</project>

[fbricon]

Yes looks pretty good