Enhance config-export for alternate destinations and Fix argument completion for config-*
Rename argument complete callbacks and bootstrap further as needed.

Argument completion for commands which use 'callback' were defined with wrong function names. Perhaps this changed in the past. 'callback' does not affect the function name.
Rename pm_update_complete().

Ensures that this function isn't mistaken for an argument completion callback.
Let config-import use alternate named config dirs as a source.