Before this PR

So we already have impersonation features in Symfony (https://symfony.com/doc/current/security/impersonating_user.html) and we have two twig helper functionsimpersonation_exit_url andimpersonation_exit_path which both work with the configuration parameter for the switch user.

If the developer changes the switch parameter (_switch_user), then these helper functions will dynamically update the_switch_user=_exit type urls/paths.

However, to switch TO a user, hand crafted urls with?_switch_user=MYIDENTIFIER likehttp://example.com/somewhere?_switch_user=thomas need to be hand crafted currently.

The problem

if we now go and change_switch_user to be something else, like_want_to_be_this_user in the Symfony configuration (Because the boss told us to do that), then all our exit path/urls will dynamically update, but our hard coded ?_switch_user=MYIDENTIFIER` will stop working.

The solution this PR provides

The solution this PR provides is to provide a new Twig Helper function for the impersonation path only, taking into account the configured value in Symfony config of the parameter (default is still_switch_user but can be anything like_want_to_be_this_user as per the docs)

This new twig function can be used as such:

<ahref="{{ impersonation_path('mike') }}">Impersonate Mike</a>

This would output?_want_to_be_this_user=mike or if the default parameter still used would be?_switch_user=mike

The PR repurposes the existing code to generate the paths and is backward compatible.