Refactor and update RocketChat bridge

* Add support for editing/deleting messages
* Add support for uploading files
* Add support for avatars
* Use the Rocket.Chat.Go.SDK
* Use the rest and streaming api

vendor/github.com/matterbridge/Rocket.Chat.Go.SDK/models/channel.go

@@ -0,0 +1,39 @@
+package models
+
+import "time"
+
+type Channel struct {
+	ID    string `json:"_id"`
+	Name  string `json:"name"`
+	Fname string `json:"fname,omitempty"`
+	Type  string `json:"t"`
+	Msgs  int    `json:"msgs"`
+
+	ReadOnly  bool `json:"ro,omitempty"`
+	SysMes    bool `json:"sysMes,omitempty"`
+	Default   bool `json:"default"`
+	Broadcast bool `json:"broadcast,omitempty"`
+
+	Timestamp *time.Time `json:"ts,omitempty"`
+	UpdatedAt *time.Time `json:"_updatedAt,omitempty"`
+
+	User        *User    `json:"u,omitempty"`
+	LastMessage *Message `json:"lastMessage,omitempty"`
+
+	// Lm          interface{} `json:"lm"`
+	// CustomFields struct {
+	// } `json:"customFields,omitempty"`
+}
+
+type ChannelSubscription struct {
+	ID          string   `json:"_id"`
+	Alert       bool     `json:"alert"`
+	Name        string   `json:"name"`
+	DisplayName string   `json:"fname"`
+	Open        bool     `json:"open"`
+	RoomId      string   `json:"rid"`
+	Type        string   `json:"c"`
+	User        User     `json:"u"`
+	Roles       []string `json:"roles"`
+	Unread      float64  `json:"unread"`
+}