implement pg_sequences

[NathanGabrielson]

Following the spec outlined here

[github-actions]

	Main	PR
covering_index_scan_postgres	1477.77/s	1477.47/s	-0.1%
index_join_postgres	267.11/s	267.45/s	+0.1%
index_join_scan_postgres	286.56/s	284.57/s	-0.7%
index_scan_postgres	14.97/s	14.87/s	-0.7%
oltp_point_select	2863.69/s	2866.08/s	0.0%
oltp_read_only	2276.83/s	2267.43/s	-0.5%
select_random_points	183.04/s	181.64/s	-0.8%
select_random_ranges	1147.16/s	1149.48/s	+0.2%
table_scan_postgres	14.67/s	14.60/s	-0.5%
types_table_scan_postgres	6.61/s	6.58/s	-0.5%

[github-actions]

	Main	PR
Total	42090	42090
Successful	18014	18014
Failures	24076	24076
Partial Successes1	5372	5372

	Main	PR
Successful	42.7988%	42.7988%
Failures	57.2012%	57.2012%

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. ↩