* Using el::Configurations Class init easylog
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* add logs config constant
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* add config check function
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* add config get function
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* logs config set function
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* update
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* update InitLog function
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* fix clang-format
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* update server_config.template
Signed-off-by: Nwxyu <xy.wang@zilliz.com>

* update changelog
Signed-off-by: Nwxyu <xy.wang@zilliz.com>