Update nofile flag in Docker to run Solana

Currently, the Solana Docker container does not start because it
requires `nofile` to be at least 500000, and the default behavior is
1024.

This fixes the documentation and running script to properly set the ulimit to
500000.

web3.js/bin/localnet.sh

@@ -88,6 +88,7 @@ up)
       --publish 8900:8900
       --publish 9900:9900
       --tty
+      --ulimit nofile=500000
       --env "RUST_LOG=$RUST_LOG"
     )
     if [[ -n $network ]]; then