Moved error tracking from sql.py to sql_io.py

sql_io.py: put_table(): Use sql.distinct_table() to uniquify input table, instead of DISTINCT ON. This avoids letting PostgreSQL create a sort temp table to store the output of the DISTINCT ON, which is not automatically removed until the end of the connection, causing database bloat that can use up the available disk space.

sql_gen.py: suffixed_table(): Use concat()

sql_gen.py: with_default_table(): Remove no longer used overwrite param

sql.py: distinct_table(): Return new table instead of renaming input table so that columns that use input table will continue to work correctly

sql_gen.py: Moved NamedCol check from with_default_table() to with_table()

sql.py: distinct_table(): Fixed bug where empty distinct_on cols needed to create a table with one sample row, instead of returning the original table, because this indicates that the full set of distinct_on columns are all literal values and should only occur once

sql.py: run_query(): DuplicateKeyException: Fixed bug where only constraint names matching a certain format were interpreted as DuplicateKeyExceptions. Support constraint names with the name and table separated by ".", not just "_".

sql.py: run_query(): Exception parsing: Match patterns only at the beginning of the exception message to avoid matching embedded messages in causes and literal values

sql.py: Added distinct_table()