Authorizing an individual serving a term of confinement to petition a court to modify or reduce the sentence under certain circumstances; providing that a certain petitioner is entitled to assistance of counsel and, if indigent, representation by the Office of the Public Defender; and authorizing a certain person to apply to the Appellate Court of Maryland for leave to appeal a certain order in a certain manner and within a certain period of time after the court passes a certain order in accordance with the provisions of the Act.