[FEATURE REQUEST] add output and bare args to export_key gpg function

[leifliddy]

Is your feature request related to a problem? Please describe.
Request to add output and bare feature to the export_key gpg module function.

Describe the solution you'd like
The output functionality would allow exported key data to be written to disk.
The bare functionality -- when implemented would cause the exported_keys function to return a standard result/comment dict by default.
The raw output could be returned by setting bare=True