Add bucket tags in product buckets

[bautisflow]

Is your feature request related to a problem? Please describe.
When declaring buckets in products, the possibility to create custom tags should tags, expanding the ones already created by default, which are device and group.

Describe the solution you'd like
An additional field with device and group tags greyed out and the possibility to add additional tags.

Describe alternatives you've considered
The only alternative that comes to mind is to create the bucket manually before any data from a device associated to the product reaches the platform.

[alvarolb]

Done! Will be included in next 6.1.0 release.