Prepare Forest for public RPC access

[LesnyRumcajs]

To have the public RPC Forest node (see #4766), we need to tackle some of its requirements.

Security consideration - proxy

#5190

We don't want to allow direct access to the Forest node. The proxy should allow filtering allowed RPC methods, e.g., disallow costly Filecoin.ChainExchange and ideally, allow rate limiting for certain methods so that the node is not flooded with computationally expensive calls.

Note that eventually we might want to ship our own proxy #4595

RPC benchmarking (good to have)

#5191

We want to assess how well Forest fares compared to other Filecoin implementations and itself (to avoid performance regression and celebrate improvements).