Refactor RPC messages to query storage maps by slot ID instead of name

A `StorageSlotName` contains both a `String` that uniquely identifies a slot, as well as a `StorageSlotId`, that is derived (hashed) from the name.

It may make sense to change RPC queries to request slots by slot ID instead of slot name, under the assumption that querying by slot ID would be more efficient (should be validated).

I'm not sure if this applies to basically whever we use a `slot_name` in `rpc.proto` or just for requests like `MapEntries` and `StorageMapDetailRequest`.

This then requires changing the DB schema to also index by slot ID and include the slot ID next to the slot name in the `account_storage_map_values` table.

Context:
- https://github.com/0xMiden/miden-node/pull/1440#discussion_r2605465555
- https://github.com/0xMiden/miden-node/pull/1440#discussion_r2605477023