Remove standalone service mode, and use launch to instead. usage:  ./mo-service -launch ./etc/launch-mem-engine/launch.toml

Approved by: @nnsgmsone

- support FileService do Write CSV data
- init schema support CVS params, in `pkg/util/metric/metric.go`, `pkg/util/trace/schema.go`
- adapt config[fileservice] to get stringwriter obj, in `pkg/util/export/fs_writer.go`
- add [cn.fileservice] in cn-service.toml
- add [[fileservice]] in log-service.toml
- mo-service support metric/trace/log/... collection,  in `pkg/cnservice/server.go`, `pkg/dnservice/store.go`, `pkg/logservice/service.go`

Approved by: @yingfeng, @daviszhen, @aptend, @fengttt, @reusee, @cnutshell, @zhangxu19830126, @lni

Manage CNStore metadata at the CN node. Provide data for CN and HAKeeper's heartbeat process

Approved by: @nnsgmsone, @daviszhen, @reusee, @lni

sql: refactor external table with Process.FileService

init file service on CN and pass to frontend

Co-authored-by: fengttt <fengttt@gmail.com>

cnservice: initialize hakeeper client, txn sender, txn client lazily

Approved by: @zhangxu19830126, @nnsgmsone

cnservice: init hakeeper client

cnservice: init txn sender

cnservice: init txn client

frontend: add wrappedTAETx, wrappedTAEEngine; rename InitDB to InitTAE

frontend: use TxnOperator instead of moengine.Txn

txn: add get txn metadata to txnOperator

replace engine.Snapshot with TxnOperator

Co-authored-by: zhangxu <zhangxu19830126@gmail.com>

1. Connect the cn-service with the frontend and the computation engine.
2. Change the configuraion mechanism to the general method. Remove the auto-generated configuration.

Approved by: @zhangxu19830126, @yingfeng, @fengttt, @aptend, @reusee, @nnsgmsone, @lni