Remove from_ps update function

The functionality provided by the from_ps update function has been
absorbed into the ps2couch python script.
Remove import-pslms-* console scripts

The import-pslms-* console scripts are deprecated. Call ps2couch
directly, instead.
Remove deprecated main() functions

people/membership/group_main() were wrappers around the actual main()
function for use by console scripts. They are deprecated. Add example
invocations of ps2couch at the beginning of the file.