Added unified Seafile (CE and PRO) installer for Debian
Added unified Seafile (CE and PRO) installer for Debian

haiwen/seafile-server-installer,shoeper/seafile-server-installer,felag/seafile-server-installer,seafile/seafile-server-installer,SeafileDE/seafile-server-installer,necrevistonnezr/seafile-server-installer,syncwerk/syncwerk-server-installer