[docs] remote connection - add refs about the changes require on the server side

[benipeled]

api_address should be set to 0.0.0.0 in order to allow remote connection

[bhalevy]

We usually don\t do that for security reasons, since the API has no auth nor encryption.

The recommended MO should be to ssh to the node and scylla-cli locally there.

[benipeled]

Ofc, we'll add it with a CLEAR clarification about the meaning of this change
(since scylla-cli supports remote connection, we should add some note about this requirement)