feat: implement StateSearchMsg and StateSearchMsgLimited RPC APIs

[hanabi1224]

Summary of changes

As part of #3639

Note: This PR is based on #3783
Note: The return_dec field in the response is ignored for now, related tracking issues: #3784 and #3769

Changes introduced in this pull request:

• implement StateSearchMsg and StateSearchMsgLimited RPC APIs

     Running `target/debug/forest-tool api compare /home/me/fr/snapshots/calibnet/forest_snapshot_calibnet_2023-12-06_height_1150811.forest.car.zst --filter StateSearch -n 200`
| RPC Method                           | Forest | Lotus |
|--------------------------------------|--------|-------|
| Filecoin.StateSearchMsg (753)        | Valid  | Valid |
| Filecoin.StateSearchMsgLimited (753) | Valid  | Valid |

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

[lemmih]

Hmm, okay, dealing with all of the different return types is rough. Let's just set return_dec to {} for now.

[elmattic]

Looks good.