feat: add context manager for reserve and lock

• Adding lock and reserve context managers.
  Reserve is used to reserve a resource, lock must be executed for the same user that reserved during 1 minute. Once lock is acquired it will be owned by user until user is releasing it.
  Additional information regarding the labgrid scheduling procedure can be seen here: https://labgrid.readthedocs.io/en/stable/usage.html#place-scheduling
• Implement parallel execution for coordinator instances running on the same host. Each instance requires a unique port and unique log dir.
• Tests added.