CmsBootstrap - Fix handling of --user on Standalone and Backdrop

[totten]

Consider commands like this:

cv url -L --user=admin civicrm/admin
cv http -L --user=admin civicrm/admin

This fixes bugs when running those on Standalone and Backdrop.

Before

The success depends on the bootstrap mechanism, e.g.

• Older bootstrap (e.g. --level=full; Bootstrap.php) ==> 🟢
• Newer bootstrap (e.g. --level=cms-full; CmsBootstrap.php) ==> 🔴

The failure shows a message like:

The "--login" option requires specifying an active user/contact ("--user=X").                                                                           

The message is confusing because you have already requested --user=admin... it's just that the --user option isn't working.

I believe the real problems are:

• For Standalone, CmsBootstrap is trying to manipulate $loggedInUserId, and there seems to be some subtlety/brittleness in how this variable works.
• For Backdrop, user_load() doesn't seem to work with those arguments.

After

• For Standalone, switch to authx_login(), which has more core test-coverage.

  (Note: Ordinarily, I would hesitate about calling authx_* from a low-level class like CmsBootstrap, as we're not guaranteed to have authx everywhere. But Standalone, it should be guaranteed.)

• For Backdrop, switch to user_load_by_name().

Comment

• Initially noticed this problem on test-results for Bootstrap - Switch default boot process. Update docs. #145.