Update mpc param for AVP-demo

Description

For the issue #604 (closed).

• Update MPC parameter to improve tracking accuracy, especially for the heading error at the terminal trajectory point to park precisely in a parking space.
• Rename the mpc.param.yaml to mpc_lgsvl.param.yaml.
• Add new file mpc_vehicle.param.yaml for the real vehicle implementation. The default value is the same as the mpc_lgsvl.param.yaml.

Before

After

Notes for Reviewer

Please test with the ms2.launch and ms3.launch.

Checklist

• Documentation was updated