HSEARCH-1533 Make MoreLikeThis handle embedded fields

Make TypeMetadata.getAllDocumentFieldMetadata() return embedded fields
Add test to make sure embedded fields are handled by MoreLikeThis
HSEARCH-1536 Add flag in DocumentTypeMetadata representing an id field from an @IndexedEmbedded object

Add test in MoreLikeThis to ignore embedded object ids.
HSEARCH-1533 Improve More Like This documentation

Add embedded ids in the exclusion list of fields
Make the enumeration clearer
HSEARCH-1533 Provides better error report when fields are excluded
HSEARCH-1536 Split MoreLikeThis tests in smaller functional blocks
HSEARCH-1545 Support for compressed fields in More Like This