Merge bitcoin/bitcoin#31391: util: Drop boost posix_time in ParseISO8601DateTime

faf70cc994 Remove wallet::ParseISO8601DateTime, use ParseISO8601DateTime instead (MarcoFalke)
2222aecd5f util: Implement ParseISO8601DateTime based on C++20 (MarcoFalke)

Pull request description:

  `boost::posix_time` in `ParseISO8601DateTime` has many issues:

  * It parses random strings that are clearly invalid and returns a time value for them, see [1] below.
  * None of the separators `-`, or `:`, or `T`, or `Z` are validated.
  * It may crash when running under a hardened C++ library, see https://github.com/bitcoin/bitcoin/issues/28917.
  * It has been unmaintained for years, so reporting or fixing any issues will most likely be useless.
  * It pulls in a third-party dependency, when the functionality is already included in vanilla C++20.

  Fix all issues by replacing it with a simple helper function written in C++20.

  Fixes https://github.com/bitcoin/bitcoin/issues/28917.

  [1] The following patch passes on current master:

  ```diff
  diff --git a/src/wallet/test/rpc_util_tests.cpp b/src/wallet/test/rpc_util_tests.cpp
  index 32f6f5ab46..c1c94c7116 100644
  --- a/src/wallet/test/rpc_util_tests.cpp
  +++ b/src/wallet/test/rpc_util_tests.cpp
  @@ -12,6 +12,14 @@ BOOST_AUTO_TEST_SUITE(wallet_util_tests)

   BOOST_AUTO_TEST_CASE(util_ParseISO8601DateTime)
   {
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("964296"), 242118028800);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("244622"), 15023836800);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("+INfINITy"), 9223372036854);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("7000802 01"), 158734166400);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("7469-2 +INfINITy"), 9223372036854);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("maXimum-datE-time"), 253402300799);
  +    BOOST_CHECK_EQUAL(ParseISO8601DateTime("577737     114maXimum-datE-time"), 253402300799);
  +
       BOOST_CHECK_EQUAL(ParseISO8601DateTime("1970-01-01T00:00:00Z"), 0);
       BOOST_CHECK_EQUAL(ParseISO8601DateTime("1960-01-01T00:00:00Z"), 0);
       BOOST_CHECK_EQUAL(ParseISO8601DateTime("2000-01-01T00:00:01Z"), 946684801);
  ```

ACKs for top commit:
  hebasto:
    ACK faf70cc994, I have reviewed the code and it looks OK.
  dergoegge:
    utACK faf70cc994

Tree-SHA512: 9dd745a356d04acf6200e13a6af52c51a9e2a0eeccea110093ce5da147b3c669c0eda918e46db0164c081a78c8feae3fe557a4759bea18449a8ff2d090095931

test/lint/lint-includes.py

@@ -20,7 +20,7 @@ from lint_ignore_dirs import SHARED_EXCLUDED_SUBTREES
 EXCLUDED_DIRS = ["contrib/devtools/bitcoin-tidy/",
                 ] + SHARED_EXCLUDED_SUBTREES
 
-EXPECTED_BOOST_INCLUDES = ["boost/date_time/posix_time/posix_time.hpp",
+EXPECTED_BOOST_INCLUDES = [
                            "boost/multi_index/detail/hash_index_iterator.hpp",
                            "boost/multi_index/hashed_index.hpp",
                            "boost/multi_index/identity.hpp",