Migrate to stateless app.App (#17542)

* add request context

* move initialialization to server

* use app interface instead of global app functions

* remove app context from webconn

* cleanup

* remove duplicated services

* move context to separate package

* remove finalize init method and move content to NewServer function

* restart workers and schedulers after adding license for tests

* reflect review comments

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/request/context.go

@@ -0,0 +1,99 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package request
+
+import (
+	"context"
+
+	"github.com/mattermost/mattermost-server/v5/model"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
+)
+
+type Context struct {
+	t              i18n.TranslateFunc
+	session        model.Session
+	requestId      string
+	ipAddress      string
+	path           string
+	userAgent      string
+	acceptLanguage string
+
+	context context.Context
+}
+
+func NewContext(ctx context.Context, requestId, ipAddress, path, userAgent, acceptLanguage string, session model.Session, t i18n.TranslateFunc) *Context {
+	return &Context{
+		t:              t,
+		session:        session,
+		requestId:      requestId,
+		ipAddress:      ipAddress,
+		path:           path,
+		userAgent:      userAgent,
+		acceptLanguage: acceptLanguage,
+		context:        ctx,
+	}
+}
+
+func EmptyContext() *Context {
+	return &Context{
+		t:       i18n.T,
+		context: context.Background(),
+	}
+}
+
+func (c *Context) T(translationID string, args ...interface{}) string {
+	return c.t(translationID, args...)
+}
+func (c *Context) Session() *model.Session {
+	return &c.session
+}
+func (c *Context) RequestId() string {
+	return c.requestId
+}
+func (c *Context) IpAddress() string {
+	return c.ipAddress
+}
+func (c *Context) Path() string {
+	return c.path
+}
+func (c *Context) UserAgent() string {
+	return c.userAgent
+}
+func (c *Context) AcceptLanguage() string {
+	return c.acceptLanguage
+}
+
+func (c *Context) Context() context.Context {
+	return c.context
+}
+
+func (c *Context) SetSession(s *model.Session) {
+	c.session = *s
+}
+
+func (c *Context) SetT(t i18n.TranslateFunc) {
+	c.t = t
+}
+func (c *Context) SetRequestId(s string) {
+	c.requestId = s
+}
+func (c *Context) SetIpAddress(s string) {
+	c.ipAddress = s
+}
+func (c *Context) SetUserAgent(s string) {
+	c.userAgent = s
+}
+func (c *Context) SetAcceptLanguage(s string) {
+	c.acceptLanguage = s
+}
+func (c *Context) SetPath(s string) {
+	c.path = s
+}
+func (c *Context) SetContext(ctx context.Context) {
+	c.context = ctx
+}
+
+func (c *Context) GetT() i18n.TranslateFunc {
+	return c.t
+}