py-agent: rename mmc.plugins.samba4.samba to mmc.plugins.samba4.samba4
py-agent: enable SamDB again - it seems it is working now
py-agent: Implement SambaAD.isUserEnabled()
py_agent: Implement listDomainMembers() xmlrpc
py_agent: Check for 'username' type - should be string

For some strange reason, it it bool now, hm
web-samba4: List domain memeber computers - no filters at the moment, just list
web-samba4: comment out "delete machine" command - imho, not implemented in Samba