Add the ability to rename parameters

This commit introduces functionality to rename parameters. The parameter map is defined just like the env map.
If renamed params have been defined, the ScriptHandler:
* checks if the new parameter is already present in parameters.yml, in which case it skips the parameter
* checks if the old parameter is present in parameters.yml, if it isn't the parameter is skipped
* It adds the new parameter with the old value to the parameter list.
The old parameter is then deleted as it normally would be (unless keep-outdated is set to true).
Renames are passed from top to bottom, so, if a parameter is renamed again the new rename can be appended at the bottom.

Functionality is documented in the README.