Core: Add a `index.query.parse.allow_unmapped_fields` setting that fails if queries refer to unmapped fields.

The percolator and filter parsing for aliases should forcefully enforce strict query parsing.

Strict parsing for percolator and filter alias parsing is only enforced on indices created after to upgrade to `1.4.0`

PR for #6664
This is enforced later on in QueryParseContext#failIfFieldMappingNotFound