Move obsolete rpc endpoints to separate api for removal (#16500)

* Move obsolete rpc methods to separate api for removal

* Remove obsolete method from docs

* Fix test using obs method

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

@@ -26,7 +26,6 @@ gives a convenient interface for the RPC methods.
 - [getConfirmedBlock](jsonrpc-api.md#getconfirmedblock)
 - [getConfirmedBlocks](jsonrpc-api.md#getconfirmedblocks)
 - [getConfirmedBlocksWithLimit](jsonrpc-api.md#getconfirmedblockswithlimit)
-- [getConfirmedSignaturesForAddress](jsonrpc-api.md#getconfirmedsignaturesforaddress)
 - [getConfirmedSignaturesForAddress2](jsonrpc-api.md#getconfirmedsignaturesforaddress2)
 - [getConfirmedTransaction](jsonrpc-api.md#getconfirmedtransaction)
 - [getEpochInfo](jsonrpc-api.md#getepochinfo)
@@ -740,58 +739,6 @@ Result:
 {"jsonrpc":"2.0","result":[5,6,7],"id":1}
 ```
 
-### getConfirmedSignaturesForAddress
-
-**DEPRECATED: Please use getConfirmedSignaturesForAddress2 instead**
-
-Returns a list of all the confirmed signatures for transactions involving an
-address, within a specified Slot range. Max range allowed is 10,000 Slots
-
-#### Parameters:
-
-- `<string>` - account address as base-58 encoded string
-- `<u64>` - start slot, inclusive
-- `<u64>` - end slot, inclusive
-
-#### Results:
-
-The result field will be an array of:
-
-- `<string>` - transaction signature as base-58 encoded string
-
-The signatures will be ordered based on the Slot in which they were confirmed in, from lowest to highest Slot
-
-#### Example:
-
-Request:
-```bash
-curl http://localhost:8899 -X POST -H "Content-Type: application/json" -d '
-  {
-    "jsonrpc": "2.0",
-    "id": 1,
-    "method": "getConfirmedSignaturesForAddress",
-    "params": [
-      "6H94zdiaYfRfPfKjYLjyr2VFBg6JHXygy84r3qhc3NsC",
-      0,
-      100
-    ]
-  }
-'
-```
-
-Result:
-```json
-{
-  "jsonrpc": "2.0",
-  "result": [
-    "35YGay1Lwjwgxe9zaH6APSHbt9gYQUCtBWTNL3aVwVGn9xTFw2fgds7qK5AL29mP63A9j3rh8KpN1TgSR62XCaby",
-    "4bJdGN8Tt2kLWZ3Fa1dpwPSEkXWWTSszPSf1rRVsCwNjxbbUdwTeiWtmi8soA26YmwnKD4aAxNp8ci1Gjpdv4gsr",
-    "4LQ14a7BYY27578Uj8LPCaVhSdJGLn9DJqnUJHpy95FMqdKf9acAhUhecPQNjNUy6VoNFUbvwYkPociFSf87cWbG"
-  ],
-  "id": 1
-}
-```
-
 ### getConfirmedSignaturesForAddress2
 
 Returns confirmed signatures for transactions involving an