Move API Reference (#23777)

* merge mattermost-api-reference unchanged

* api: update repostiory paths

* api: drop GitPod for api (for now)

* api: improved node_modules target

* api: relocate GitHub actions to root

* Update .github/workflows/api.yml

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>

* fix cache-dependency-path

* adopt node-version-file

* pin versions for uses

* tidy steps/runs

* api/.gitpod.yml: tidy

* api: rm now unused .gitlab-ci.yml

---------

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>

api/v4/source/sharedchannels.yaml

@@ -0,0 +1,116 @@
+  "/api/v4/sharedchannels/{team_id}":
+    get:
+      tags:
+        - shared channels
+      summary: Get all shared channels for team.
+      description: |
+        Get all shared channels for a team.
+
+        __Minimum server version__: 5.50
+
+        ##### Permissions
+        Must be authenticated.
+      operationId: GetAllSharedChannels
+      parameters:
+        - name: team_id
+          in: path
+          description: Team Id
+          required: true
+          schema:
+            type: string
+        - name: page
+          description: The page to select.
+          in: query
+          schema:
+            type: integer
+            default: 0
+        - name: per_page
+          description: The number of sharedchannels per page.
+          in: query
+          schema:
+            type: integer
+            default: 0
+      responses:
+        "200":
+          description: Shared channels fetch successful. Result may be empty.
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/SharedChannel"
+        "400":
+          $ref: "#/components/responses/BadRequest"
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "403":
+          $ref: "#/components/responses/Forbidden"
+      x-code-samples:
+        - lang: Go
+          source: |
+            import "github.com/mattermost/mattermost-server/v5/model"
+
+            Client := model.NewAPIv4Client("https://your-mattermost-url.com")
+            Client.Login("email@domain.com", "Password1")
+
+            teamID := "4xp9fdt77pncbef59f4k1qe83o"
+
+            shared_channels, err := Client.GetAllSharedChannels(teamID, 0, 100)
+        - lang: curl
+          source: |
+            curl -X POST \
+              'http://your-mattermost-url.com/api/v4/sharedchannels/4xp9fdt77pncbef59f4k1qe83o' \
+              -H 'Authorization: Bearer kno8tcdotpbx3dj1gzcbx9jrqy'
+
+  "/api/v4/sharedchannels/remote_info/{remote_id}":
+    get:
+      tags:
+        - shared channels
+      summary: Get remote cluster info by ID for user.
+      description: |
+        Get remote cluster info based on remoteId.
+
+        __Minimum server version__: 5.50
+
+        ##### Permissions
+        Must be authenticated and user must belong to at least one channel shared with the remote cluster.
+      operationId: GetRemoteClusterInfo
+      parameters:
+        - name: remote_id
+          in: path
+          description: Remote Cluster GUID
+          required: true
+          schema:
+            type: string
+      responses:
+        "200":
+          description: Remote cluster info retrieval successful
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RemoteClusterInfo"
+        "400":
+          $ref: "#/components/responses/BadRequest"
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "403":
+          $ref: "#/components/responses/Forbidden"
+        "404":
+          $ref: "#/components/responses/NotFound"
+      x-code-samples:
+        - lang: Go
+          source: |
+            import "github.com/mattermost/mattermost-server/v5/model"
+
+            Client := model.NewAPIv4Client("https://your-mattermost-url.com")
+            Client.Login("email@domain.com", "Password1")
+
+            remoteID := "4xp9fdt77pncbef59f4k1qe83o"
+
+            info, err := Client.GetRemoteClusterInfo(remoteID)
+        - lang: curl
+          source: |
+            curl -X POST \
+              'http://your-mattermost-url.com/api/v4/sharedchannels/getremote/4xp9fdt77pncbef59f4k1qe83o' \
+              -H 'Authorization: Bearer kno8tcdotpbx3dj1gzcbx9jrqy'
+