Merge bitcoin/bitcoin#34483: refactor: Use SpanReader over DataStream

fa0677d131 refactor: Use SpanReader over DataStream (MarcoFalke)
fad3eb3956 refactor: Use SpanReader over DataStream (MarcoFalke)
fa06e26764 refactor: [qt] Use SpanReader to avoid two vector copies (MarcoFalke)
fabd4d2e2e refactor: Avoid UB in SpanReader::ignore (MarcoFalke)
fa20bc2ec2 refactor: Use empty() over eof() in the streams interface (MarcoFalke)
fa879db735 test: Read debug log for self-checking comment (MarcoFalke)

Pull request description:

  This changes all places, where possible, to use SpanReader over DataStream. This makes the code easier to read and reason about, because `SpanReader` can never write data. Also, the code should be minimally faster, because it avoids a full redundant copy of the whole vector of bytes.

ACKs for top commit:
  stickies-v:
    re-ACK fa0677d131
  achow101:
    ACK fa0677d131
  janb84:
    re ACK fa0677d131
  sipa:
    crACK fa0677d131

Tree-SHA512: 1d9f43fc6e71d481cf7b8f8457f479745ee331734649e9e2c2ab00ce5d317112796c77afc328612ed004e65ac5c16fc92279d760cfb012cfddce9098c4af810f

src/test/net_tests.cpp

@@ -876,10 +876,9 @@ BOOST_AUTO_TEST_CASE(initial_advertise_from_version_message)
                                         std::span<const unsigned char> data,
                                         bool is_incoming) -> void {
         if (!is_incoming && msg_type == "addr") {
-            DataStream s{data};
             std::vector<CAddress> addresses;
 
-            s >> CAddress::V1_NETWORK(addresses);
+            SpanReader{data} >> CAddress::V1_NETWORK(addresses);
 
             for (const auto& addr : addresses) {
                 if (addr == expected) {