enh: order by primary key optimize

feat(query): add avg function

fix(cluster): repair dmnodeTest

fix(query): fix sum,count,max,min function no output when input is constant value

ci: stop valgrind test for a while

fix(query): disable timestamp type arithmetic operation with var type

ci: run python test in 3.0 ci

TD-15107

fix: fix hb broken link issue

fix(cluster): repair dmnodeTest

fix: heartbeat problem