Raku module to manage Raku META files

 Raku META6 module provides a representation of the Raku META files
 specification - the META file data can be read, created , parsed and
 written in a manner that is conformant with the specification.
 .
 Where they are known about it also makes allowance for "customary" usage
 in existing software (such as installers and so forth.)
 .
 The intent of this is allow the generation and testing of META files for
 module authors, so it can provide meta-information whether the
 attributes are mandatory as per the spec and where known the places that
 "customary" attributes are used,