Moving slash-commands out of app package (#14979)

* Moving slash-commands out of app package

* Fixing golint checks

* Fixing golangci-lint

* Fixing golangci-lint errors

app/slashcommands/command_me.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package slashcommands
+
+import (
+	goi18n "github.com/mattermost/go-i18n/i18n"
+	"github.com/mattermost/mattermost-server/v5/app"
+	"github.com/mattermost/mattermost-server/v5/model"
+)
+
+type MeProvider struct {
+}
+
+const (
+	CMD_ME = "me"
+)
+
+func init() {
+	app.RegisterCommandProvider(&MeProvider{})
+}
+
+func (me *MeProvider) GetTrigger() string {
+	return CMD_ME
+}
+
+func (me *MeProvider) GetCommand(a *app.App, T goi18n.TranslateFunc) *model.Command {
+	return &model.Command{
+		Trigger:          CMD_ME,
+		AutoComplete:     true,
+		AutoCompleteDesc: T("api.command_me.desc"),
+		AutoCompleteHint: T("api.command_me.hint"),
+		DisplayName:      T("api.command_me.name"),
+	}
+}
+
+func (me *MeProvider) DoCommand(a *app.App, args *model.CommandArgs, message string) *model.CommandResponse {
+	return &model.CommandResponse{
+		ResponseType: model.COMMAND_RESPONSE_TYPE_IN_CHANNEL,
+		Type:         model.POST_ME,
+		Text:         "*" + message + "*",
+		Props: model.StringInterface{
+			"message": message,
+		},
+	}
+}