zilencer: Add a simple management command to create a RemoteZulipServer.
zilencer: Add a simple management command to create a RemoteZulipServer.

This saves us from having to go into a `manage.py shell` to do this,
and adds a bit more structure like the usage message.

zulip/zulip,showell/zulip,synicalsyntax/zulip,rht/zulip,hackerkid/zulip,dhcrzf/zulip,jackrzhang/zulip,timabbott/zulip,eeshangarg/zulip,brainwane/zulip,timabbott/zulip,brainwane/zulip,kou/zulip,shubhamdhama/zulip,punchagan/zulip,dhcrzf/zulip,jackrzhang/zulip,kou/zulip,hackerkid/zulip,synicalsyntax/zulip,brainwane/zulip,rht/zulip,zulip/zulip,andersk/zulip,punchagan/zulip,tommyip/zulip,shubhamdhama/zulip,shubhamdhama/zulip,zulip/zulip,punchagan/zulip,brainwane/zulip,andersk/zulip,timabbott/zulip,timabbott/zulip,shubhamdhama/zulip,kou/zulip,eeshangarg/zulip,zulip/zulip,showell/zulip,brainwane/zulip,rht/zulip,hackerkid/zulip,punchagan/zulip,punchagan/zulip,shubhamdhama/zulip,kou/zulip,andersk/zulip,rishig/zulip,rht/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,showell/zulip,eeshangarg/zulip,hackerkid/zulip,punchagan/zulip,punchagan/zulip,rishig/zulip,jackrzhang/zulip,kou/zulip,synicalsyntax/zulip,synicalsyntax/zulip,shubhamdhama/zulip,synicalsyntax/zulip,tommyip/zulip,hackerkid/zulip,eeshangarg/zulip,brainwane/zulip,rht/zulip,zulip/zulip,rishig/zulip,rishig/zulip,jackrzhang/zulip,rishig/zulip,dhcrzf/zulip,brainwane/zulip,timabbott/zulip,tommyip/zulip,eeshangarg/zulip,showell/zulip,zulip/zulip,tommyip/zulip,dhcrzf/zulip,jackrzhang/zulip,rht/zulip,showell/zulip,hackerkid/zulip,tommyip/zulip,andersk/zulip,synicalsyntax/zulip,tommyip/zulip,dhcrzf/zulip,tommyip/zulip,shubhamdhama/zulip,rishig/zulip,dhcrzf/zulip,hackerkid/zulip,rishig/zulip,andersk/zulip,jackrzhang/zulip,showell/zulip,zulip/zulip,kou/zulip,jackrzhang/zulip,synicalsyntax/zulip,timabbott/zulip,showell/zulip,dhcrzf/zulip,timabbott/zulip,andersk/zulip,rht/zulip