Expose public/ API as submodule (#23345)

* model -> public/model

* plugin -> public/plugin

* public/model/utils -> public/utils

* platform/shared/mlog -> public/shared/mlog

* platform/shared/i18n -> public/shared/i18n

* platform/shared/markdown -> public/shared/markdown

* platform/services/timezones -> public/shared/timezones

* channels/einterfaces -> einterfaces

* expose public/ submodule

* go mod tidy

* .github: cache-dependency-path, setup-go-work

* modules-tidy for public/ too

* remove old gomodtidy

server/public/model/push_response.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+const (
+	PushStatus         = "status"
+	PushStatusOk       = "OK"
+	PushStatusFail     = "FAIL"
+	PushStatusRemove   = "REMOVE"
+	PushStatusErrorMsg = "error"
+)
+
+type PushResponse map[string]string
+
+func NewOkPushResponse() PushResponse {
+	m := make(map[string]string)
+	m[PushStatus] = PushStatusOk
+	return m
+}
+
+func NewRemovePushResponse() PushResponse {
+	m := make(map[string]string)
+	m[PushStatus] = PushStatusRemove
+	return m
+}
+
+func NewErrorPushResponse(message string) PushResponse {
+	m := make(map[string]string)
+	m[PushStatus] = PushStatusFail
+	m[PushStatusErrorMsg] = message
+	return m
+}