[slapos_hypermedia] Upgrade to new erp5_hal_json_style.

A few tests can be taken out of this BT to be put in erp5_hal_json_style.
slap: Add getInformation() x2 and getOpenOrderList().
slapos CLI: add slapos list and slapos info.
Interface tests: tell what class is wrong.

Instead of just failing with no clue except that 0 is equal to 0...