Timezone feature (#8185)

* Add supported timezones into config

Remove Timezone list creation in favor of timezone from configs

Add Timezone field to Users table

Clean up format of SupportedTimezones in config

* Remove unwanted change

* Add test for updating user timezone

* Add empty map[string]string if Timezone is null

* Add EnableTimezoneSelection config

* Revert back to map[string]string for ClientConfig

* Refactor SupportedTimezones into timezones.json

* Include timezones.json in TestConfigFlag

* Add timezone api endpoint

* Bump varchar size to 256 and setMaxSize in user_store

* Refactor LoadConfig to LoadConfig and LoadTimezoneConfig

* Remove unnecessary argument in LoadConfig, mail_test

* Add test for timezone endpoint

* Add license header

* Refactor timezones endpoint to system.go

* Add system base route to timezone endpoint

* db timezone upgrade in db v4.9

* Avoid saving SupportedTimezones to config.json

* Add timezonePath support in config

* Remove EnableTimezoneSelection from config

* Use return statement without return parameter

* Refactor test for SupportedTimezones

* Check for supportedTimezone != nil instead of using len

* Decouple SupportedTimezones out of Config

* Fix failing test

* Add LastTeamIconUpdate back in upgrade.go

* Write timezone config in config_flag_test

* Add code fallback for default timezone support

model/user.go

@@ -71,6 +71,7 @@ type User struct {
 	LastPictureUpdate  int64     `json:"last_picture_update,omitempty"`
 	FailedAttempts     int       `json:"failed_attempts,omitempty"`
 	Locale             string    `json:"locale"`
+	Timezone           StringMap `json:"timezone"`
 	MfaActive          bool      `json:"mfa_active,omitempty"`
 	MfaSecret          string    `json:"mfa_secret,omitempty"`
 	LastActivityAt     int64     `db:"-" json:"last_activity_at,omitempty"`
@@ -86,6 +87,7 @@ type UserPatch struct {
 	Props       StringMap `json:"props,omitempty"`
 	NotifyProps StringMap `json:"notify_props,omitempty"`
 	Locale      *string   `json:"locale"`
+	Timezone    StringMap `json:"timezone"`
 }
 
 type UserAuth struct {
@@ -208,6 +210,10 @@ func (u *User) PreSave() {
 		u.SetDefaultNotifications()
 	}
 
+	if u.Timezone == nil {
+		u.Props = make(map[string]string)
+	}
+
 	if len(u.Password) > 0 {
 		u.Password = HashPassword(u.Password)
 	}
@@ -302,6 +308,10 @@ func (u *User) Patch(patch *UserPatch) {
 	if patch.Locale != nil {
 		u.Locale = *patch.Locale
 	}
+
+	if patch.Timezone != nil {
+		u.Timezone = patch.Timezone
+	}
 }
 
 // ToJson convert a User to a json string