[ticket/12602] Add command to print the cron list
* Stephannos/ticket/12602:
[ticket/12602] Fix language key removal.
[ticket/12602] Rectify language keys.
[ticket/12602] Fix test mistake.
[ticket/12602] Fix language var mistakes.
[ticket/12602] Add types, change description of cron:list.
[ticket/12602] Fix internationalisation of cron_list.php
[ticket/12602] Fix spaces issues.
[ticket/12602] Coding style correction.
[ticket/12602] Fix coding style mistakes.
[ticket/12602] Headers updated.
[ticket/12602] Changes to respect coding style and to factorize code.
[ticket/12602] Cleanup tests
[ticket/12602] Add function get_tasks.
[ticket/12602] Correction of the output message for the cron list
[ticket/12602] Add files to print the cron list and test files.