Better support for COPY FROM statements

[zachmu]

This change makes it possible to load data into tables without the full set of columns specified. pg_dump will not include generated columns in its output.

Also fixes a bug for the load from file use case, which only supported CSV files before (now supports the same set of formats).

[github-actions]

	Main	PR
covering_index_scan_postgres	375.89/s	370.09/s	-1.6%
index_join_postgres	154.07/s	154.19/s	0.0%
index_join_scan_postgres	184.59/s	183.85/s	-0.5%
index_scan_postgres	12.48/s	12.59/s	+0.8%
oltp_point_select	2772.58/s	2781.32/s	+0.3%
oltp_read_only	1877.70/s	1878.50/s	0.0%
select_random_points	111.98/s	113.01/s	+0.9%
select_random_ranges	133.03/s	132.59/s	-0.4%
table_scan_postgres	11.84/s	11.78/s	-0.6%
types_table_scan_postgres	5.49/s	5.52/s	+0.5%

[github-actions]

	Main	PR
Total	42090	42090
Successful	15351	15358
Failures	26739	26732
Partial Successes1	5234	5238

	Main	PR
Successful	36.4718%	36.4885%
Failures	63.5282%	63.5115%

${\color{red}Regressions (1)}$

alter_table

QUERY:          copy attest from stdin;
EXPECTED ERROR: extra data after last expected column
RECEIVED ERROR: extra data after last expected column (errno 1105) (sqlstate HY000)

${\color{lightgreen}Progressions (6)}$

constraints

QUERY: COPY COPY_TBL FROM '/home/runner/work/doltgresql/doltgresql/testing/go/regression/data/constrf.data';

identity

QUERY: COPY itest9 (b, c) FROM stdin;

numeric

QUERY: COPY width_bucket_test (operand_num) FROM stdin;

rowsecurity

QUERY: COPY t3(id, a,b,c) FROM stdin;

triggers

QUERY: insert into trig_table values
  (1, 'one a'),
  (1, 'one b'),
  (2, 'two a'),
  (2, 'two b'),
  (3, 'three a'),
  (3, 'three b');

QUERY: drop table refd_table, trig_table;

Footnotes

1. These are tests that we're marking as Successful, however they do not match the expected output in some way. This is due to small differences, such as different wording on the error messages, or the column names being incorrect while the data itself is correct. ↩

[fulghum]

Looks good! Nice work expanding COPY FROM support!