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/channel_stats.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+type ChannelStats struct {
+	ChannelId       string `json:"channel_id"`
+	MemberCount     int64  `json:"member_count"`
+	GuestCount      int64  `json:"guest_count"`
+	PinnedPostCount int64  `json:"pinnedpost_count"`
+	FilesCount      int64  `json:"files_count"`
+}
+
+func (o *ChannelStats) MemberCount_() float64 {
+	return float64(o.MemberCount)
+}
+
+func (o *ChannelStats) GuestCount_() float64 {
+	return float64(o.GuestCount)
+}
+
+func (o *ChannelStats) PinnedPostCount_() float64 {
+	return float64(o.PinnedPostCount)
+}