feat: unify servers and mysql server in datanode (#172)

* address PR comments

address PR comments

use 3306 for mysql server's default port

upgrade metric to version 0.20

move crate "servers" out of "common"

make mysql io threads count configurable in config file

add snafu backtrace for errors with source

use common-server error for mysql server

add test for grpc server

refactor testing codes

fix rustfmt check

start mysql server in datanode

move grpc server codes from datanode to common-servers

feat: unify servers

* rebase develop and resolve conflicts

* remove an unnecessary todo

Co-authored-by: luofucong <luofucong@greptime.com>

src/common/runtime/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 [dependencies]
 common-error = { path = "../error" }
 common-telemetry = { path = "../telemetry" }
-metrics = "0.18"
+metrics = "0.20"
 once_cell = "1.12"
 paste = "1.0"
 snafu = { version = "0.7", features = ["backtraces"] }