Check for availability of snap name first, instead of directly reserving it

[keshavbhatt]

Expected behaviour

There should be an option in the flow of registering a snap name with the store in which the user is asked to confirm the reservation of name. This behaviour would be similar to Windows-store developer dashboard which is present there to prevent accidental name reservations.

Steps to reproduce the problem

• Go to snapcraft.io/account
• Try to register/reserve a snap name for your snap and notice the registration/reservation happens straight away without any sort of confirmation step.

My Suggestion would be: have a step where developers can first check the availability of name before directly registering it with a confirmation step to make sure they have not made any typo etc in the name.

Why this is a concern: I myself have many names reserved in the account, few got registered with spelling mistakes, few remain reserved cause i changed my mind later to name the snap differently. This become problematic when we know that there no easy one click way to unregister and delete the reserved name (I opened a separate issue for that here)

[cristinadresch]

@jkfran can we check if we have the API available for this?