MM-33903 rename slash commands & permission (#17494)

- rename slash commands
    - "remote" -> "secure-connection"
    - "share" -> "share-channel"
- change status icons to text (translated)
- remove channel invite "Description" field
- rename permission "manage_remote_clusters" -> "manage_secure_connections"

model/shared_channel.go

@@ -106,7 +106,6 @@ func (sc *SharedChannel) PreUpdate() {
 type SharedChannelRemote struct {
 	Id                string `json:"id"`
 	ChannelId         string `json:"channel_id"`
-	Description       string `json:"description"`
 	CreatorId         string `json:"creator_id"`
 	CreateAt          int64  `json:"create_at"`
 	UpdateAt          int64  `json:"update_at"`
@@ -136,10 +135,6 @@ func (sc *SharedChannelRemote) IsValid() *AppError {
 		return NewAppError("SharedChannelRemote.IsValid", "model.channel.is_valid.id.app_error", nil, "ChannelId="+sc.ChannelId, http.StatusBadRequest)
 	}
 
-	if len(sc.Description) > 64 {
-		return NewAppError("SharedChannelRemote.IsValid", "model.channel.is_valid.description.app_error", nil, "description="+sc.Description, http.StatusBadRequest)
-	}
-
 	if sc.CreateAt == 0 {
 		return NewAppError("SharedChannelRemote.IsValid", "model.channel.is_valid.create_at.app_error", nil, "id="+sc.ChannelId, http.StatusBadRequest)
 	}
@@ -172,7 +167,6 @@ type SharedChannelRemoteStatus struct {
 	SiteURL          string `json:"site_url"`
 	LastPingAt       int64  `json:"last_ping_at"`
 	NextSyncAt       int64  `json:"next_sync_at"`
-	Description      string `json:"description"`
 	ReadOnly         bool   `json:"readonly"`
 	IsInviteAccepted bool   `json:"is_invite_accepted"`
 	Token            string `json:"token"`