[SQL] Remove ajxp_simple_store create from mq.sql

It's already in conf.sql, it was not up to date,
and postgresql before 9.x doesn't support
CREATE TABLE IF NOT EXISTS

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@fiducial.net>
[SQL] BIG sql schema changes in conf.sql

Put real PRIMARY KEY (not useless int)
Put PRIMARY KEY for sqlite
Remove DEFAULT NULL in sqlite
Fix style in files

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@fiducial.net>