Configurable logger for connection pool

[DifferentialOrange]

There is a way to configure Logger for a connection (even though it may be not a modern Go way to deal with log customization):

go-tarantool/connection.go

Line 329 in ce667de

Logger Logger

but no way to do so for connection pool:

go-tarantool/pool/connection_pool.go

Line 326 in ce667de

log.Printf("tarantool: connect to %s failed: %s\n", instance.Name, err)

go-tarantool/pool/connection_pool.go

Line 730 in ce667de

log.Printf("tarantool: connect to %s failed: %s\n", name, err)

so if you need to customize it in any way, you need to overwrite a global logger. It would be nice to be able to pass a custom logger to a pool constructor in case one needs it. (For example, we used it for a TCF client to hide expected connection error messages.) It also may be nice to rework existing Logger interface to something build-in like log or slog interface/type.

[oleg-jukovec]

In progress:

#555