Major rewrite of table/column name output escaping system wide.

Major rewrite of table/column name output escaping system wide.

Centralized logic in database-identifier that returns
database-identifier objects.  These allow us to coerce to a canonical
output name and have both its escaped and unescaped version available.
Previously the logic for converting from various sql-expressions,
symbols and strings into names that will be sent to the database, was
done all over the place and with different logic in each location

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