Negate the toggles in the 'Create event' view

[klstilling]

At the moment the toggles are:

• 'Don't limit the price' (toggled on by default)
• 'No deadline for participation' (toggled on by default)

I think that it would be better to negate them, e.g. rename them to

• 'Limit the price' (off by default)
• 'Registration deadline' (off by default)