Allow to specify more meta-data for alias

See https://github.com/eikek/sharry/issues/187#issuecomment-804761563

Alias allows to define a validitd, but nothing else. It should allow to define all other data, too. Like view count and whether it is published immediately or not.

Start with the linked issue comment to understand the existing validity-only alias behavior, then locate the alias model and API entry points. Identify which metadata fields are intended to be configurable and add tests covering view count and immediate publication; done means the agreed metadata is accepted when defining an alias.

Written by the indexing model from the issue text.