API: Add HTTPOutputHandler::setCLIFormatter
Fixes https://github.com/silverstripe/silverstripe-framework/issues/6835
This provides detailed errors (but not warnings or notices) in CLI calls
on live environments.
It does this by adding a 2nd argument to our output handler,
CliFormatter. This formatter will be used when Director::is_cli() is
true.
API CHANGE: Debug::showError(), Debug::showLines(), Debug::log(), and Debug::header() removed
NEW: Logging provided
ZendLog has been removed and monolog introduced instead as a dependency.
The “ErrorLogger” injection point is now the used as the logger that
errors are fed into, and implements PSR-3’s Psr\Log\LoggerInterface.
The SS_ERROR_LOG setting expect a Monolog Logger to be provided as the
ErrorLogger.
