Allow nextval() to take a regclass instance

[fulghum]

Allows the nextval() function to take a regclass parameter. Also changes the output function of regclass so that the returned relation name is schema-qualified if the schema is not on search_path.

This change also moves the GetCurrentSchemas() function into a new settings package to break a package import cycle. The new settings package is intended for low-level functions that access settings, without dependencies on other packages.

Fixes: #850

[github-actions]

	Main	PR
Total	42090	42090
Successful	12864	12867
Failures	29226	29223
Partial Successes1	4892	4892

	Main	PR
Successful	30.5631%	30.5702%
Failures	69.4369%	69.4298%

${\color{lightgreen}Progressions}$

sequence

QUERY: SELECT nextval('sequence_test'::regclass);

QUERY: SELECT nextval('sequence_test'::regclass);

QUERY: SELECT nextval('sequence_test'::regclass);

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. ↩

[Hydrocharged]

LGTM! One of the changes are a little concerning though