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/bundle_info_test.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBundleInfoForPath(t *testing.T) {
+	dir, err := os.MkdirTemp("", "mm-plugin-test")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	path := filepath.Join(dir, "plugin.json")
+	f, err := os.Create(path)
+	require.NoError(t, err)
+	_, err = f.WriteString(`{"id": "foo"}`)
+	f.Close()
+	require.NoError(t, err)
+
+	info := BundleInfoForPath(dir)
+	assert.Equal(t, info.Path, dir)
+	assert.NotNil(t, info.Manifest)
+	assert.Equal(t, info.ManifestPath, path)
+	assert.NoError(t, info.ManifestError)
+}