Command migration for single shard, multi-shard and custom commands

[AshwinKul28]

This PR migrates multiple DiceDB commands to support both multi-shard and single-shard scenarios. The migration follows a structured flow for each command type as described below.

Multi-Shard Commands
The following commands are migrated with support for multi-shard processing:

1. MSET
2. MGET
3. SINTER
4. SDIFF
5. JSON.MGET

For the COPY and RENAME commands, the flow includes preprocessing, followed by decomposition and composition steps to manage multi-shard data efficiently. For the remaining multi-shard commands, only decomposition and composition steps are involved.

Single-Shard Commands
The following commands are migrated with support for single-shard processing:

1. JSON.SET
2. JSON.GET
3. JSON.TYPE
4. JSON.INGEST
5. JSON.HGETALL
6. JSON.STRAPPEND
7. Dump
8. Restore

These single-shard commands follow a scatter-gather approach with a straightforward flow, where each command operates directly within the target shard, without the need for complex decomposition.

[JyotinderSingh]

Looks like a conflict came up. @AshwinKul28 please feel free to resolve conflict and merge immediately.

[apoorvyadav1111]

Amazing work, Cant wait to see it merged. left comments more like notes for future.

[AshwinKul28]

@apoorvyadav1111 @JyotinderSingh any idea why LPush tests are failing? Also HTTP context cancelled error is coming out of nowhere :(

[JyotinderSingh]

Thanks for the massive effort @AshwinKul28, and thanks for all the debugging help @apoorvyadav1111. We are now much closer to a fully multi-threaded system!