Rpc: enable getConfirmedBlock and getConfirmedTransaction to return confirmed (not yet finalized) data (#16142)

* Add Blockstore block and tx apis that allow unrooted responses

* Add TransactionStatusMessage, and send on bank freeze; also refactor TransactionStatusSender

* Track highest slot with tx-status writes complete

* Rename and unpub fn

* Add commitment to GetConfirmed input configs

* Support confirmed blocks in getConfirmedBlock

* Support confirmed txs in getConfirmedTransaction

* Update sigs-for-addr2 comment

* Enable confirmed block in cli

* Enable confirmed transaction in cli

* Review comments

* Rename blockstore method

docs/src/developing/clients/jsonrpc-api.md

@@ -463,6 +463,7 @@ Returns identity and transaction information about a confirmed block in the ledg
   "jsonParsed" encoding attempts to use program-specific instruction parsers to return more human-readable and explicit data in the `transaction.message.instructions` list. If "jsonParsed" is requested but a parser cannot be found, the instruction falls back to regular JSON encoding (`accounts`, `data`, and `programIdIndex` fields).
   - (optional) `transactionDetails: <string>` - level of transaction detail to return, either "full", "signatures", or "none". If parameter not provided, the default detail level is "full".
   - (optional) `rewards: bool` - whether to populate the `rewards` array. If parameter not provided, the default includes rewards.
+  - (optional) [Commitment](jsonrpc-api.md#configuring-state-commitment); "processed" is not supported. If parameter not provided, the default is "finalized".
 
 #### Results:
 
@@ -856,6 +857,7 @@ Returns transaction details for a confirmed transaction
 - `<object>` - (optional) Configuration object containing the following optional fields:
   - (optional) `encoding: <string>` - encoding for each returned Transaction, either "json", "jsonParsed", "base58" (*slow*), "base64". If parameter not provided, the default encoding is "json".
   "jsonParsed" encoding attempts to use program-specific instruction parsers to return more human-readable and explicit data in the `transaction.message.instructions` list. If "jsonParsed" is requested but a parser cannot be found, the instruction falls back to regular JSON encoding (`accounts`, `data`, and `programIdIndex` fields).
+  - (optional) [Commitment](jsonrpc-api.md#configuring-state-commitment); "processed" is not supported. If parameter not provided, the default is "finalized".
 
 #### Results: