backlog: remove mem trace

[lispc]

after scroll-tech/scroll-prover#32 is used,

we can set vm.LogConfig{EnableMemory: true} to false. i guess doing this can reduce blockResult size 5-10times.

(I remember maybe we have to change 2 place? One is for the realtime websocket , the other is getBlockResultByHash fetching/regerating for old block trace? )

[mask-pp]

Does that mean we can turning off Trace by params?

[mask-pp]

Or just don't load memory trace?

[icemelon]

@lispc I think #134 should be enough, right? we only need to disable the trace in the VM config. No need to change any API such as getBlockResultByHash.