GitLab

**Description**
Integrate monitor into Superbench.

**Major Revision**
- Initialize, start and stop monitor in SB executor.
- Parse the monitor data in SB runner and merge into benchmark results.
- Specify ReduceType for monitor metrics, such as MAX, MIN and LAST.
- Add monitor configs into config file.

**Description**
Add the initial version of Monitor.

**Major Revision**
- Add `Monitor` class to launch background process for monitoring.
- Add `MonitorRecord` class to save the data one time capturing.