Migrate AlertBox components to the new Alert component

[gtsiolis]

Problem to solve

Back in #8783, we've added the next iteration of the alert component which introduces component variants for using the alert component for informing users, alerting users, etc.

Currently, there're two more Alert-like components which include InfoBox and AlertBox, see example screenshots below.

Component: InfoBox	Component: Alert, Variant: Info

Component: AlertBox	Component: Alert, Variant: Warning

Proposal

Migrate InfoBox (8 component instances) and AlertBox (5 component instances) components to the new Alert component. ➿

[gtsiolis]

In the spirit of minimum viable change, I've updated the issue and split the InfoBox component migration to a separate issue in #10205. Thanks @KevSlashNull for picking this up!