Rework on email queue, primarily add Illuminate\Support\Fluent and Illuminate\Support\SerializableClosure to aid building queue support for mailing.

Signed-off-by: crynobone <crynobone@gmail.com>
Simplify setting up email configuration during app boot-up.

Signed-off-by: crynobone <crynobone@gmail.com>
Cleanup code and update testcases.

Signed-off-by: crynobone <crynobone@gmail.com>
Small whitespace cleanup.

Signed-off-by: crynobone <crynobone@gmail.com>