Merge bitcoin/bitcoin#27511: rpc: Add test-only RPC getaddrmaninfo for new/tried table address count

28bac81a34 test: add functional test for getaddrmaninfo (stratospher)
c8eb8dae51 rpc: Introduce getaddrmaninfo for count of addresses stored in new/tried table (stratospher)

Pull request description:

  implements https://github.com/bitcoin/bitcoin/issues/26907. split off from #26988 to keep RPC, CLI discussions separate.

  This PR introduces a new RPC `getaddrmaninfo`which returns the count of addresses in the new/tried table of a node's addrman broken down by network type. This would be useful for users who want to see the distribution of addresses from different networks across new/tried table in the addrman.

  ```jsx
  $ getaddrmaninfo

  Result:
  {                   (json object) json object with network type as keys
    "network" : {     (json object) The network (ipv4, ipv6, onion, i2p, cjdns)
      "new" : n,      (numeric) number of addresses in new table
      "tried" : n,    (numeric) number of addresses in tried table
      "total" : n     (numeric) total number of addresses in both new/tried tables from a network
    },
    ...
  }
  ```

  ### additional context from [original PR](https://github.com/bitcoin/bitcoin/pull/26988)

  1. network coverage tests were skipped because there’s a small chance that addresses from different networks could hash to the same bucket and cause count of different network addresses in the tests to fail. see https://github.com/bitcoin/bitcoin/pull/26988#discussion_r1137596851.
  2. #26988 uses this RPC in -addrinfo CLI. Slight preference for keeping the RPC hidden since this info will mostly be useful to only super users. see https://github.com/bitcoin/bitcoin/pull/26988#discussion_r1173964808.

ACKs for top commit:
  0xB10C:
    ACK 28bac81a34
  willcl-ark:
    reACK 28bac81a34
  achow101:
    ACK 28bac81a34
  brunoerg:
    reACK 28bac81a34
  theStack:
    Code-review ACK 28bac81a34

Tree-SHA512: 346390167e1ebed7ca5c79328ea452633736aff8b7feefea77460e04d4489059334ae78a3f757f32f5fb7827b309d7186bebab3c3760b3dfb016d564a647371a

src/test/fuzz/rpc.cpp

@@ -110,6 +110,7 @@ const std::vector<std::string> RPC_COMMANDS_SAFE_FOR_FUZZING{
     "generate",
     "generateblock",
     "getaddednodeinfo",
+    "getaddrmaninfo",
     "getbestblockhash",
     "getblock",
     "getblockchaininfo",