USD "save as" after a Stage created from file

[kimuss]

Is your feature request related to a problem? Please describe.
Currently, once create a stage from file, we can not save the same stage as a different path or change file format. It would be nice to have an option to change path or file format of the same stage.

Describe the solution you'd like
in USD Layer Editor, a button to change path o "save as", not just "save edits" as it is now.

Describe alternatives you've considered
main features are the possibility to create copy of that stage, change file format or the main path with of file

thank you

[maya-usd-git-sync]

Issue synced internally to EMSUSD-840