Setup: Merge PreConfigSetup into Setup.php
Follows-up
41ea7e2fefff65.
The following previously happened between PreConfigSetup and Setup
and must now happen either before it, after it, or moved inside it.
* WebStart: Detect missing composer.
This must be after Autoloader/Vendor but before the first call to
wfDebugLog (or other loggers) so that we can output a more descriptive
error instead of a generic "Unknown class" fatal error.
Moving it to before Setup is too early, and after is too late.
Move it to within Setup.php and make it work in CLI mode.
* WebStart: Install header callback
Moving it to before Setup is too early, and after is too late.
Move it to within Setup.php (no-op in CLI mode).
* WebStart/Maintenance: Load LocalSetings.
Must be between PreConfigSetup and Setup.
Move to Setup.php to maintain execution order.
Utilise MW_CONFIG_File for custom handling in Maintenance.php.
* WebStart: Initialise output buffering
Utilise (new) MW_SETUP_CALLBACK hook.
* WebStart: Display NoLocalSettings.php
Utilise MW_CONFIG_CALLBACK hook.
* Maintenance: Setting $wgLocalisationCacheConf, calling Maintenance::finalSetup.
Utilise (new) MW_SETUP_CALLBACK hook.
Change-Id: I633a6ff235b4275391c48034c0525d2fbfa3fecd