Refactor secure id generation

[EdgarOrtegaRamirez]

Every time a Box is created, it will try to generate a non-duplicate secure_id. This will prevent the app from crashing in the case that the secure_id is duplicate.

[a-chernykh]

Thanks for the contribution, @EdgarOrtegaRamirez I like the changes in generate_secure_id, but at the same time I would prefer to keep uniqueness validation to ensure integrity (just in case if we decide to allow to edit secure_id in future).

[EdgarOrtegaRamirez]

@andreychernih done