…t tests` commit

… and nVersion private and sometimes const` commit

… nType and nVersion` commit

…s. Add Base58 tests.

…ault pattern, NODISCARD

…xcept wallet/gui)

f9ee0f3 Add comments to CustomUintFormatter (Pieter Wuille)
4eb5643 Convert everything except wallet/qt to new serialization (Pieter Wuille)
2b1f85e Convert blockencodings_tests to new serialization (Pieter Wuille)
73747af Convert merkleblock to new serialization (Pieter Wuille)
d06fedd Add SER_READ and SER_WRITE for read/write-dependent statements (Russell Yanofsky)
6f9a1e5 Extend CustomUintFormatter to support enums (Russell Yanofsky)
769ee5f Merge BigEndian functionality into CustomUintFormatter (Pieter Wuille)

Pull request description:

  The next step of changes from bitcoin#10785.

  This:
  * Adds support for enum serialization to `CustomUintFormatter`, used in `CAddress` for service flags.
  * Merges `BigEndian` into `CustomUintFormatter`, used in `CNetAddr` for port numbers.
  * Converts everything (except wallet and gui) to use the new serialization framework.

ACKs for top commit:
  MarcoFalke:
    re-ACK f9ee0f3, only change is new documentation commit for CustomUintFormatter 📂
  ryanofsky:
    Code review ACK f9ee0f3. Just new commit adding comment since last review
  jonatack:
    Code review re-ACK f9ee0f3 only change since last review is an additional commit adding Doxygen documentation for `CustomUintFormatter`.

Tree-SHA512: e7a0a36afae592d5a4ff8c81ae04d858ac409388e361f2bc197d9a78abca45134218497ab2dfd6d031e0cce0ca586cf857077b7c6ce17fccf67e2d367c1b6cd4

71f016c Remove old serialization primitives (Pieter Wuille)
92beff1 Convert LimitedString to formatter (Pieter Wuille)
ef17c03 Convert wallet to new serialization (Pieter Wuille)
65c589e Convert Qt to new serialization (Pieter Wuille)

Pull request description:

  This is the final step 🥳 of the serialization improvements extracted from bitcoin#10785.

  It converts the LimitedString wrapper to a new-style formatter, and updates the wallet and Qt code to use the new serialization framework. Finally all remaining old primitives are removed.

ACKs for top commit:
  jonatack:
    ACK 71f016c reviewed diff, builds/tests/re-fuzzed.
  laanwj:
    Code review ACK 71f016c

Tree-SHA512: d952194bc73259f6510bd4ab1348a1febbbf9862af30f905991812fb0e1f23f15948cdb3fc662be54d648e8f6d95b11060055d2e7a8c2cb5bf008224870b1ea1