Add nopersist and noreplication options

Config option "disable-all-persistence" stops Redis from writing
or reading an AOF or RDB.  If you are on Linux and are running
with the proper permissions (a "ulimit -l" of 'unlimited', typically
only settable by root, or the CAP_IPC_LOCK capability), this option
also disables the paging of any Redis memory to disk.

Config option "disable-replication" stops Redis from becoming a master
or replica or migrating keys to other nodes or participating
in a cluster.

disable-all-persistence automatically enables disable-replication.

disable-all-persisitence also stops Redis from creating any
background-I/O threads since they would have zero work to do anyway.

You *can* use disable-replication independently if you want to store
data to disk but turn off all network replication/clustering/migration.

These options can only be set at launch.  You cannot alter these
settings after Redis starts.  Once your server is running with
any of these isolation guarantees, it will remain isolated.

These options are designed to create isolated and "pure" Redis instances
for data that must never leave Redis except by direct client access.

Of course, someone could always just scan your entire database from
a client and copy it that way, but it's still not a live replication channel.

Without these options, it can be tricky to track down every "disable
storage" option.

Without the "disable-replication" option, there isn't any way to stop
Redis from replicating over the network except using firewalls/ACLs.