Implement the collapsing/expanding logic for the first panel

[menor]

• Timepicker is expanded by default
• Only one element can be expanded at a time.
• all three elements can be collapsed

Do we want to collapse the header when an element is expanded @fabiennepimenta ?

[fabiennepimenta]

Rules:

• We never touch in the header height. Always stays the same.
• Only one element can be expanded at a time.
• When I click on a collapsed element, I expand that one and close the current open;
• When I click in an expanded one, I close that one and stay on the ‘Clean mode’ All collapsed.
• All three elements can be collapsed

Overview:

[menor]

It makes sense (for now :P) Can you move the behaviour part to #69 ?

[menor]

This one is done