Merge #19607: [p2p] Add Peer struct for per-peer data in net processing

8e35bf5906 scripted-diff: rename misbehavior members (John Newbery)
1f96d2e673 [net processing] Move misbehavior tracking state to Peer (John Newbery)
7cd4159ac8 [net processing] Add Peer (John Newbery)
aba03359a6 [net processing] Remove CNodeState.name (John Newbery)

Pull request description:

  We currently have two structures for per-peer data:

  - `CNode` in net, which should just contain connection layer data (eg socket, send/recv buffers, etc), but currently also contains some application layer data (eg tx/block inventory).
  - `CNodeState` in net processing, which contains p2p application layer data, but requires cs_main to be locked for access.

  This PR adds a third struct `Peer`, which is for p2p application layer data, and doesn't require cs_main. Eventually all application layer data from `CNode` should be moved to `Peer`, and any data that doesn't strictly require cs_main should be moved from `CNodeState` to `Peer` (probably all of `CNodeState` eventually).

  `Peer` objects are stored as shared pointers in a net processing global map `g_peer_map`, which is protected by `g_peer_mutex`. To use a `Peer` object, `g_peer_mutex` is locked, a copy of the shared pointer is taken, and the lock is released. Individual members of `Peer` are protected by different mutexes that guard related data. The lifetime of the `Peer` object is managed by the shared_ptr refcount.

  This PR adds the `Peer` object and moves the misbehaving data from `CNodeState` to `Peer`. This allows us to immediately remove 15 `LOCK(cs_main)` instances.

  For more motivation see #19398

ACKs for top commit:
  laanwj:
    Code review ACK 8e35bf5906
  troygiorshev:
    reACK 8e35bf5906 via `git range-diff master 9510938 8e35bf5`
  theuni:
    ACK 8e35bf5906.
  jonatack:
    ACK 8e35bf5906 keeping in mind Cory's comment (https://github.com/bitcoin/bitcoin/pull/19607#discussion_r470173964) for the follow-up

Tree-SHA512: ad84a92b78fb34c9f43813ca3dfbc7282c887d55300ea2ce0994d134da3e0c7dbc44d54380e00b13bb75a57c28857ac3236bea9135467075d78026767a19e4b1

src/rpc/net.cpp

@@ -197,7 +197,7 @@ static UniValue getpeerinfo(const JSONRPCRequest& request)
         if (fStateStats) {
             if (IsDeprecatedRPCEnabled("banscore")) {
                 // banscore is deprecated in v0.21 for removal in v0.22
-                obj.pushKV("banscore", statestats.nMisbehavior);
+                obj.pushKV("banscore", statestats.m_misbehavior_score);
             }
             obj.pushKV("synced_headers", statestats.nSyncHeight);
             obj.pushKV("synced_blocks", statestats.nCommonHeight);