the entry name, 1 to 128 letters, digits, dots, dashes or underscores
the XACML XML document
Optionaloptions: WriteOptions
enabled (default true), isRoot and description
{ ok: true, id, kind }, or { ok: false, why } carrying its
error code for no directory, a bad name, a document that does not
validate (with its problems), a second root or a refused entry
Validates a policy document and writes it as a directory entry, then tells the change observer.