[feat req] SFTP / FTPS support from webinterface

[derhagen]

It would be nice to have SFTP or at least FTPS options in the webinterface. My Resellers aren't able to configure user access via ssh.

[jc268429]

+1 from me. However i do foresee messiness with authentication

[mvarian]

+1. One of our big marketing points to clients is security and we'd like to just disable FTP altogether and force SFTP/FTPS.

[TGates71]

@Dukecitysolutions we should look into this when the panel or root zadmin domain have ssl certs (sencrypt sub-function?) Same with postfix

[TGates71]

Added to private task manager.