Merge bitcoin/bitcoin#28687: C++20 std::views::reverse

2925bd537c refactor: use c++20 std::views::reverse instead of reverse_iterator.h (stickies-v)

Pull request description:

  C++20 introduces [`std::ranges::views::reverse`](https://en.cppreference.com/w/cpp/ranges/reverse_view), which allows us to drop our own `reverse_iterator.h` implementation and also makes it easier to chain views (even though I think we currently don't use this).

ACKs for top commit:
  achow101:
    ACK 2925bd537c
  maflcko:
    ACK 2925bd537c 🎷

Tree-SHA512: 567666ec44af5d1beb7a271836bcc89c4c577abc77f522fcc18bc6d4de516ae9b0df766d0bfa6dd217569e6878331c2aee1d9815620860375e3510dad7fed476

contrib/devtools/copyright_header.py

@@ -19,7 +19,6 @@ EXCLUDE = [
     'src/qt/bitcoinstrings.cpp',
     'src/chainparamsseeds.h',
     # other external copyrights:
-    'src/reverse_iterator.h',
     'src/test/fuzz/FuzzedDataProvider.h',
     'src/tinyformat.h',
     'src/bench/nanobench.h',