Add association between FabricAdapter and Port

As a course of implementing PortCollection and Port schemas,
this commit adds a new association to describe the links
between FabricAdapter and Port.

 - FabricAdapter may be "connected_to" one or more ports,
 - A port may also be "connecting" one or more items.

The generic associations of 'containing' and 'contained_by'
are considered, but they are for the physically "containing" items.

Related schemas are:

- https://redfish.dmtf.org/schemas/v1/Port.v1_8_0.json

```
       "Links": {
           "description": "The links to other resources that are related to this resource.",
            "properties": {
                "AssociatedEndpoints": {
                    "description": "An array of links to the endpoints at the other end of the link.",
                    "items": {
                        "$ref": "http://redfish.dmtf.org/schemas/v1/Endpoint.json#/definitions/Endpoint"
                    },
                    "longDescription": "This property shall contain an array of links to resources of type Endpoint that represent the endpoints to which this port is connected.",
                    "readonly": true,
                    "type": "array"
                },
                "AssociatedEndpoints@odata.count": {
                    "$ref": "http://redfish.dmtf.org/schemas/v1/odata-v4.json#/definitions/count"
                },
```

- https://redfish.dmtf.org/schemas/v1/FabricAdapter.v1_5_0.json

```
                "Ports": {
                    "$ref": "http://redfish.dmtf.org/schemas/v1/PortCollection.json#/definitions/PortCollection",
                    "description": "The link to the collection of ports that exist on the fabric adapter.",
                    "longDescription": "This property shall contain a link to a Resource Collection of type PortCollection.",
                    "readonly": true
                },
```

Change-Id: I2cc8caf0128bf1cfa619312e689fe02039977e44
Signed-off-by: Myung Bae <myungbae@us.ibm.com>

gen/xyz/openbmc_project/Inventory/Connector/Port/meson.build

@@ -0,0 +1,15 @@
+# Generated file; do not modify.
+generated_sources += custom_target(
+    'xyz/openbmc_project/Inventory/Connector/Port__cpp'.underscorify(),
+    input: [ '../../../../../../yaml/xyz/openbmc_project/Inventory/Connector/Port.interface.yaml',  ],
+    output: [ 'common.hpp', 'server.cpp', 'server.hpp', 'client.hpp',  ],
+    depend_files: sdbusplusplus_depfiles,
+    command: [
+        sdbuspp_gen_meson_prog, '--command', 'cpp',
+        '--output', meson.current_build_dir(),
+        '--tool', sdbusplusplus_prog,
+        '--directory', meson.current_source_dir() / '../../../../../../yaml',
+        'xyz/openbmc_project/Inventory/Connector/Port',
+    ],
+)
+

gen/xyz/openbmc_project/Inventory/Connector/meson.build

@@ -14,6 +14,21 @@ generated_others += custom_target(
     ],
 )
 
+subdir('Port')
+generated_others += custom_target(
+    'xyz/openbmc_project/Inventory/Connector/Port__markdown'.underscorify(),
+    input: [ '../../../../../yaml/xyz/openbmc_project/Inventory/Connector/Port.interface.yaml',  ],
+    output: [ 'Port.md' ],
+    depend_files: sdbusplusplus_depfiles,
+    command: [
+        sdbuspp_gen_meson_prog, '--command', 'markdown',
+        '--output', meson.current_build_dir(),
+        '--tool', sdbusplusplus_prog,
+        '--directory', meson.current_source_dir() / '../../../../../yaml',
+        'xyz/openbmc_project/Inventory/Connector/Port',
+    ],
+)
+
 subdir('Slot')
 generated_others += custom_target(
     'xyz/openbmc_project/Inventory/Connector/Slot__markdown'.underscorify(),

yaml/xyz/openbmc_project/Inventory/Connector/Port.interface.yaml

@@ -0,0 +1,11 @@
+description: >
+    This defines a Port of a switch, controller, chassis, or any other device
+    that could be connected to another entity.
+
+association:
+    name: connected_to
+    description: >
+        Objects that are connected at the other end of the link.
+    reverse_name: connecting
+    required_endpoint_interfaces:
+        - xyz.openbmc_project.Inventory.Item.FabricAdapter

yaml/xyz/openbmc_project/Inventory/Item/FabricAdapter.interface.yaml

@@ -2,3 +2,12 @@ description: >
     Implement to provide fabric adapter attributes. A physical fabric adapter
     capable of connecting to an interconnect fabric. Examples include but are
     not limited to Ethernet, NVMe over Fabrics, etc.
+
+associations:
+    name: connecting
+    description: >
+        Objects that implement FabricAdapter can optionally implement the
+        connecting association to  provide links to one or more Ports.
+    reverse_name: connected_to
+    required_endpoint_interfaces:
+        - xyz.openbmc_project.Inventory.Connector.Port

yaml/xyz/openbmc_project/Inventory/Item/README.md

@@ -24,3 +24,4 @@ Document ObjectMapper association forward and reverse names as follows:
 - led and item: `{identifying, identified_by}`
   `{fault_identifying, fault_identified_by}`
 - powerSupply and item: `{powering, powered_by}`
+- FabricAdapter and port: `{connecting, connected_to}`