[INTEGRATION][SETUP] Insert script for branch setup

The objective of the script inserted in this commit is to:
* Automate the setup of new protected main branches by creating
them within a specific group and/or in a list of projects chosen by the user.
* Automate the configuration of the variables required to enable integration via CI/CD,
i.e. INTEGRATION variable.
* Automate the creation of a manifest branch having the same name with all
variables configured correctly.
* Automate the deletion of these branches and the cleanup of the variables
if it is no longer necessary to use the branches.

The script is not integrated within the pipeline flow but to be run
on spot when a new version of Yocto is passed to support, and/or for the creation
of new branches that require development of new functionality.