fast code url + code for category

[syjer]

• add the possibility to define a secret code for a given category
• add a controller that map to the following url: /event/name/code/CODE_HERE
  where code can be
  1. the generic code for accessing a category
  2. the unique code for a ticket (5 chars)
  3. a discount code

with the case 1) and 2) the user will access directly a prenotation
for 3) it will apply the discount code and send the user to the event detail page

[syjer]

this is a 1.11.x feature

[syjer]

for ticket category code:

flow is: if restricted -> take first free code and apply it (see admin reservation manager logic)
flow is: if public -> make a reservation for a single ticket

[syjer]

Should be done