Implements PowerSubsystem schema

This commit implements the Redfish PowerSubsystem schema and collects
default property values.
PowerSupplies will be implemented in the next commit.

ref:
https://www.dmtf.org/sites/default/files/standards/documents/
DSP0268_2022.2.pdf (6.86 PowerSubsystem 1.1.0)
https://redfish.dmtf.org/schemas/v1/PowerSupply.v1_1_0.json



Tested: Validator and UT passes
1. curl -k  -H "X-Auth-Token: $token" -X GET
https://${bmc}/redfish/v1/Chassis/chassis/PowerSubsystem
{
"@odata.id": "/redfish/v1/Chassis/chassis/PowerSubsystem",
"@odata.type": "#PowerSubsystem.v1_1_0.PowerSubsystem",
"Id": "PowerSubsystem",
"Name": "Power Subsystem",
"Status": {
"Health": "OK",
"State": "Enabled"
}
}

2. bad chassisID
curl -k -H "X-Auth-Token: $token" -X GET https://${bmc}
/redfish/v1/Chassis/badchassisID/PowerSubsystem/
PowerSupplies/powersupply0
{
  "error": {
    "@Message.ExtendedInfo": [
      {
        "@odata.type": "#Message.v1_1_1.Message",
        "Message": "The requested resource of type Chassis named
                   badchassisID was not found.",
        "MessageArgs": [
          "Chassis",
          "badchassisID"
        ],
        "MessageId": "Base.1.13.1.ResourceNotFound",
        "MessageSeverity": "Critical",
        "Resolution": "Provide a valid resource identifier
                      and resubmit the request."
      }
    ],
    "code": "Base.1.13.1.ResourceNotFound",
    "message": "The requested resource of type Chassis named
               badchassisID was not found."
  }
}

Signed-off-by: Chicago Duan <duanzhijia01@inspur.com>
Change-Id: I6885b1777082538eceaf7ea85a8f69966459ee43