Add vk bridge (#1372)

* Add vk bridge

* Vk bridge attachments

* Vk bridge forwarded messages

* Vk bridge sample config and code cleanup

* Vk bridge add vendor

* Vk bridge message edit

* Vk bridge: fix fetching names of other bots

* Vk bridge: code cleanup

* Vk bridge: fix shadows declaration

* Vk bridge: remove UseFileURL

vendor/github.com/SevereCloud/vksdk/v2/api/execute.go

@@ -0,0 +1,52 @@
+package api
+
+import "encoding/json"
+
+// ExecuteWithArgs a universal method for calling a sequence of other methods
+// while saving and filtering interim results.
+//
+// The Args map variable allows you to retrieve the parameters passed during
+// the request and avoids code formatting.
+//
+// 	return Args.code; // return parameter "code"
+// 	return Args.v; // return parameter "v"
+//
+// https://vk.com/dev/execute
+func (vk *VK) ExecuteWithArgs(code string, params Params, obj interface{}) error {
+	token := vk.getToken()
+
+	reqParams := Params{
+		"code":         code,
+		"access_token": token,
+		"v":            vk.Version,
+	}
+
+	resp, err := vk.Handler("execute", params, reqParams)
+
+	jsonErr := json.Unmarshal(resp.Response, &obj)
+	if jsonErr != nil {
+		return jsonErr
+	}
+
+	if resp.ExecuteErrors != nil {
+		return &resp.ExecuteErrors
+	}
+
+	return err
+}
+
+// Execute a universal method for calling a sequence of other methods while
+// saving and filtering interim results.
+//
+// https://vk.com/dev/execute
+func (vk *VK) Execute(code string, obj interface{}) error {
+	return vk.ExecuteWithArgs(code, Params{}, obj)
+}
+
+func fmtBool(value bool) string {
+	if value {
+		return "1"
+	}
+
+	return "0"
+}