Add vector name auto-complete in visualisation

[joein]

The visualisation tool requires a vector name to build a map

A user does not necessarily remembers vector names, they might be bulky or they can be autogenerated (e.g. with fastembed)

To find a vector name, one need to do some extra actions, like visiting other pages or making requests to the DB.

It would be nice to have autocomplete for vector_name field, or have available vector names somewhere in the vicinity.

If there is only one vector in a collection, then it might also be helpful to fill vector_name automatically.