device_manager_validate_identifier

[nclack]

In acquire-project/acquire-core-libs#6, I deleted a block of code that was doing identifier validation (in storage_validate).

The validation part is a good idea, but we were using device_manager_select to do it, resulting in some undesired log messages. Really it would be better to have a dedicated validation function and use that more broadly during configuration for validating device selection.

It should basically go through calling describe and confirm the type looks right.