art_brain, art_projected_gui: Use ProgramArray instead of Program

[ZdenekM]

Using ProgramArray.msg instead of Program.msg (Program.msg will serve as container for logically related instructions (program block) - e.g. assembly of one side of the trolley)

• Rewrite DB art_db: Rewrite #42
• Write helper class to deal with Program/ProgramBlock/ProgramItem
• Integrate it in art_brain
• update interface_state_manager
• Integrate it in art_projected_gui

[ZdenekM]

• art_brain now assumes that ProgramItem id is unique - but the item should be identified by block id + item id
• art_projected_gui only display the first program block

[ZdenekM]

Helper class: https://github.com/robofit/ar-table-itable/blob/master/art_utils/src/art_utils/program_helper.py