serializationFormat:xml should write XMLs which follow the formatting rules of FileVault

[kwin]

The DocView XMLs written should comply with the rules from FileVault (compare with https://jackrabbit.apache.org/filevault-package-maven-plugin/format-xml-mojo.html).

The rules are:

• Indent by 4 spaces
• all attributes on a new line (does not apply to namespace declarations)
• attributes sorted alphabetically

[kwin]

All rules except for the last one are already followed in version 1.8.0, but the attributes are not yet sorted alphabetically in https://github.com/wcm-io-frontend/aem-clientlib-generator/blob/1082c6713a7d9411c34dfa968aebb74dcd956406/lib/clientlib.js#L210-L231.

In addition the namespace declaration of cq is superfluous as no JCR property for client libraries use that namespace.