[Phase 2][YSQL] Dump tablegroups with tablespaces

[timothy-e]

Jira Link: [DB-375](https://yugabyte.atlassian.net/browse/DB-375)
respect the --no-tablespaces option

-- yb_ysql_dump.sql

CREATE TABLEGROUP grp; -- (already exists in the test)
CREATE TABLEGROUP grp_with_spc TABLESPACE tblspc;
CREATE TABLE tbl16 (a int) WITH (autovacuum_enabled = true) TABLEGROUP grp_with_spc;

-- yb_ysql_dump.out

SET default_tablespace = '';

--
-- Name: grp; Type: TABLEGROUP; Schema: -; Owner: yugabyte_test
--

CREATE TABLEGROUP grp;


ALTER TABLEGROUP grp OWNER TO yugabyte_test;


SET default_tablespace = 'tblspc';

--
-- Name: grp_with_spc; Type: TABLEGROUP; Schema: -; Owner: yugabyte_test
--

CREATE TABLEGROUP grp_with_spc;


ALTER TABLEGROUP grp_with_spc OWNER TO yugabyte_test;

...

--
-- Name: tbl16; Type: TABLE; Schema: public; Owner: yugabyte_test
--

CREATE TABLE public.tbl16 (
    a integer
)
WITH (autovacuum_enabled='true')
TABLEGROUP grp_with_spc;


ALTER TABLE public.tbl16 OWNER TO yugabyte_test;