All setUp(), tearDown(), setUpBeforeClass() and tearDownAfterClass()
must, always, call to parent, to ensure that everything is properly
set and cleaned.
While in a lot of situations this is not needed (parents may not
have anything to run), with PHPUnit >= 10 this can become more
important because we are going to move the reset code from current
placement @ runBare() to setUp()/tearDown().
Note that all the changes performed in this commit have been detected
and fixed by moodle-cs (ParentSetUpTearDownSniffTest).
While this change is not 100% required now, it's good habit
and we are checking for it since Moodle 4.4.
All the changes in this commit have been applied automatically
using the moodle.PHPUnit.TestReturnType sniff and are, exclusively
adding the ": void" return types when missing.
Three modes are initially introduced here, for use by dependent code:
1. Automatic - where accounts will be automatically created for users
2. Prompt new or existing - where the user can choose to use an existing
account or have a new account created for them.
3. Prompt existing only - where users must link an existing account.
This change also adds linked logins, for use with provisioning.
