mktables: Add fate

mktables: Add fate

Some tables are predestined to not be output; others have different
fates.  This patch creates a 'fate' field in the table data structure
which replaces the 'internal_only' field, the latter becoming just one
of the possible fates.

The SUPPRESSED and PLACEHOLDER statuses are moved to be fates.  This
makes the code cleaner in places, and allows independent setting of the
tables fate from its pod entry.

The empty slot will be filled in later