rpc: replace binary string endpoints/types

[hinto-janai]

What

Replaces RPC binary string endpoints/types by implementing monero-project/monero#9422 (comment).

This removes the planned deprecated endpoints/types i.e. get_tx_backlog_v2 will work but get_tx_backlog will return error.

RPC API changes

Removed

• /json_rpc (get_txpool_backlog)
• /json_rpc (get_output_distribution)

Added

• /json_rpc (get_txpool_backlog_v2)
• /json_rpc (get_output_distribution_v2)
• /get_txpool_backlog.bin

Same as before

• /get_output_distribution.bin

JSON representation examples

// get_txpool_backlog_v2
{
  "id": "0",
  "jsonrpc": "2.0",
  "result": {
    "backlog": [
      {
        "weight": 0,
        "fee": 0,
        "time_in_pool": 0
      }
    ],
    "status": "OK",
    "untrusted": false
  }
}

// get_output_distribution_v2
{
  "id": "0",
  "jsonrpc": "2.0",
  "result": {
    "credits": 0,
    "distributions": [
      {
        "start_height": 0,
        "base": 0,
        "distribution": [1000, 2000, 3000],
        // If `compress` is passed the above field instead be something like:
        // "compressed_data": [0, 1, 2],
        "amount": 0,
        "binary": false
      }
    ],
    "status": "OK",
    "top_hash": "",
    "untrusted": false
  }
}