Support aliases for transients #376
Description
There are various reasons that researchers may want to identify a particular transient by multiple names, but our database schema relies on the transient name being a globally unique identifier. We should design and implement a system allowing users to assign aliases to a transient.
Each alias will map to only a single transient, but each transient can have an arbitrary number of aliases. One approach is to create a new model Alias with a foreign key mapping to Transient objects. Assigning the Alias name field as the unique primary key would enforce the many-to-one mapping constraint.
The Alias model would provide the flexibility to add metadata in the future. For example, there could be fields for display_name and description providing display-friendly formatting of the alias that is not bound by the Transient name rules as well as an arbitrary text field that might explain the origin of the alias, such as another astronomical data catalog.