Align custom scripts with generic scripts, making them configurable. This has a few advantages:
- script code is more unified,
- no more hard-coded method names in scripts, which is less error prone and make it easier to rename scripts,
- no more hard coded product names in scripts, which is less error prone and make it easier to rename products,
- less hard-coded URLs and regexes in scripts, which makes auto-configuration more expressive / updatable,
Also added method `endoflife.list_configs_from_argv()` so that it is easier to manipulate scripts arguments.
