Copy weight files into node-template

[ggwpez]

Analogous to paritytech/polkadot#5064
Instead of using the default weights from frame_support, copy the files over to encourage developers to benchmark their own weights.
Concretely block_weight.rs, extrinsic_weight.rs, rocksdb_weight.rs and paritydb_weight.rs.

The parachain template needs this as well.

[bkchr]

@shawntabrizi so we can also close this issue?

[shawntabrizi]

Yes. My opinion at this moment is that the node template should be minimal, and just point to the "default substrate weights" for now.