Adds Remote Cluster related API endpoints (#27432)

* Adds Remote Cluster related API endpoints

New endpoints for the following routes are added:

- Get Remote Clusters at `GET /api/v4/remotecluster`
- Create Remote Cluster at `POST /api/v4/remotecluster`
- Accept Remote Cluster invite at `POST
/api/v4/remotecluster/accept_invite`
- Generate Remote Cluster invite at `POST
/api/v4/remotecluster/{remote_id}/generate_invite`
- Get Remote Cluster at `GET /api/v4/remotecluster/{remote_id}`
- Patch Remote Cluster at `PATCH /api/v4/remotecluster/{remote_id}`
- Delete Remote Cluster at `DELETE /api/v4/remotecluster/{remote_id}`

These endpoints are planned to be used from the system console, and
gated through the `manage_secure_connections` permission.

* Update server/channels/api4/remote_cluster_test.go

Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

* Fix AppError names

---------

Co-authored-by: Doug Lauder <wiggin77@warpmail.net>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/web/params.go

@@ -93,6 +93,14 @@ type Params struct {
 	FilterHasMember           string
 	IncludeChannelMemberCount string
 	OutgoingOAuthConnectionID string
+	ExcludeOffline            bool
+	InChannel                 string
+	NotInChannel              string
+	Topic                     string
+	CreatorId                 string
+	OnlyConfirmed             bool
+	OnlyPlugins               bool
+	ExcludePlugins            bool
 
 	//Bookmarks
 	ChannelBookmarkId string
@@ -126,7 +134,11 @@ func ParamsFromRequest(r *http.Request) *Params {
 	params.FileId = props["file_id"]
 	params.Filename = query.Get("filename")
 	params.UploadId = props["upload_id"]
-	params.PluginId = props["plugin_id"]
+	if val, ok := props["plugin_id"]; ok {
+		params.PluginId = val
+	} else {
+		params.PluginId = query.Get("plugin_id")
+	}
 	params.CommandId = props["command_id"]
 	params.HookId = props["hook_id"]
 	params.ReportId = props["report_id"]
@@ -150,6 +162,14 @@ func ParamsFromRequest(r *http.Request) *Params {
 	params.RemoteId = props["remote_id"]
 	params.InvoiceId = props["invoice_id"]
 	params.OutgoingOAuthConnectionID = props["outgoing_oauth_connection_id"]
+	params.ExcludeOffline, _ = strconv.ParseBool(query.Get("exclude_offline"))
+	params.InChannel = query.Get("in_channel")
+	params.NotInChannel = query.Get("not_in_channel")
+	params.Topic = query.Get("topic")
+	params.CreatorId = query.Get("creator_id")
+	params.OnlyConfirmed, _ = strconv.ParseBool(query.Get("only_confirmed"))
+	params.OnlyPlugins, _ = strconv.ParseBool(query.Get("only_plugins"))
+	params.ExcludePlugins, _ = strconv.ParseBool(query.Get("exclude_plugins"))
 	params.ChannelBookmarkId = props["bookmark_id"]
 	params.Scope = query.Get("scope")