StorageMap insert entry if key has not had a value set

[Braqzen]

Rust has the following map.entry("").or_insert();

It would improve UX if we had a try_insert() or insert_if_empty() method which checks if a value has been set for a key and if it has not then it inserts it.
This removes the need for higher level code to manually check if there is an entry and then insert it via another line of code if it has not been set (removing the need for an if expression at a high level)