fix: improve get_table_info

[Mateusz-Switala]

Currently, even the table has some primary key or foreign keys, we do not include these constraints when invoking get_table_info. The aim of this PR is to fix this:

CREATE TABLE public.patient (
	id BIGINT NOT NULL,
	sex TEXT,
	birthday DATE,
	description DATE,
	First Date DATE,
	admission TEXT,
	diagnosis TEXT,
	CONSTRAINT primary_key PRIMARY KEY (id),
	CONSTRAINT examination_id_fkey FOREIGN KEY (id) REFERENCES examination(id),
	CONSTRAINT laboratory_id_fkey FOREIGN KEY (id) REFERENCES laboratory(id)
	)

First 3 rows of table patient:

   id sex   birthday description First Date admission diagnosis
 2110   F 1934-02-13  1994-02-14 1993-02-10         +  RA susp.
11408   F 1937-05-02  1996-12-01 1973-01-01         +       PSS
12052   F 1956-04-14  1991-08-13       None         +       SLE

Before:

CREATE TABLE public.patient (
	id BIGINT NOT NULL,
	sex TEXT,
	birthday DATE,
	description DATE,
	First Date DATE,
	admission TEXT,
	diagnosis TEXT,
	)

First 3 rows of table patient:

      id sex    birthday description  First Date admission diagnosis
0   2110   F  1934-02-13  1994-02-14  1993-02-10         +  RA susp.
1  11408   F  1937-05-02  1996-12-01  1973-01-01         +       PSS
2  12052   F  1956-04-14  1991-08-13        None         +       SLE