test: case for alter stable

fix(query): prepare enough buffer before convert string.

refactor: use tagver and colver insteadof sversion

feat: scheduler async api

fix(stream): function error

feat: add vgroup for tsma

feat(stream): stream final session operator

feat: seperate data schema version and tag schema version

fix: some problems of rollup sma

fix(query): free the cursor when all data retrieved immediately.

for 3.0

[TD-15999]

feat(query): add apercentile function

temp close concast.py, concast_ws.py, join.py.