Rename --timeout param to --http-timeout

The --timeout parameter was already used by the
load balancer subcommand so adding it as a top-level
parameter broke the load balancer commands. This
patch renames the new --timeout top-level command
to --http-timeout so it doesn't conflict with the
existing load balancer commands.

DocImpact

Closes-Bug: #1353536
Change-Id: I3d1dd9537e546191c5905e0aa5415de5308d9c7e