feature request about editing Main Toolbar from GUI

[Norbert]

#### Proposed behaviour
User will be able to add, remove, create new buttons on Main Toolbar from GUI settings.

#### Actual behaviour
User is not able to add, remove, create new buttons on Main Toolbar from GUI settings.

#### Steps to reproduce the behaviour
Open Caja, try to find settings for editing Main Toolbar.

#### MATE general version
1.26

#### Package version
1.26.0-1ubuntu1

#### Linux Distribution
Ubuntu 22.04 LTS (development branch)

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: caja 1.26.0-1ubuntu1
ProcVersionSignature: Ubuntu 5.13.0-19.19-generic 5.13.14
Uname: Linux 5.13.0-19-generic x86_64
ApportVersion: 2.20.11-0ubuntu76
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: MATE
Date: Thu Jan 27 11:01:12 2022
InstallationDate: Installed on 2022-01-15 (11 days ago)
InstallationMedia: Ubuntu-MATE 22.04 LTS "Jammy Jellyfish" - Alpha amd64 (20220115)
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: caja
UpgradeStatus: No upgrade log present (probably fresh install)