Remove the multi-environment feature from deployer

In order to simplify the deployer, we will remove the multi-environment feature.

This means that will no longer be possible to chain multiple environments into a single deployer pipeline. Such chaining must happen at release-tools level.

The target environment will be provided as a variable.

This new feature must be developed as a merge request targeting the next-gen branch.

Here follow a table describing the expected environments for each type of package, providing the right environment will be responsibility of the caller.

Version Type	Environment
RC	preprod
patch release	release
autodeploy	gstg,gprd-cny, gprd

Merge request on ops based on nex-gen

Deployer single environment refactoring MR on ops