Merge #19706: refactor: make EncodeBase58{Check} consume Spans

356988e200 util: make EncodeBase58Check consume Spans (Sebastian Falbesoner)
f0fce0675d util: make EncodeBase58 consume Spans (Sebastian Falbesoner)

Pull request description:

  This PR improves the interfaces for the functions `EncodeBase58{Check}` by using Spans, in a similar fashion to e.g. PRs #19660, #19687. Note that on the master branch there are currently two versions of `EncodeBase58`: one that takes two pointers (marking begin and end) and another one that takes a `std::vector<unsigned char>` const-ref. The PR branch only leaves one generic Span-interface, both simplifying the interface and allowing more generic containers to be passed. The same is done for `EncodeBase58Check`, where only one interface existed but it's more generic now (e.g. a std::array can be directly passed, as done in the benchmarks).

ACKs for top commit:
  laanwj:
    Code review ACK 356988e200

Tree-SHA512: 47cfccdd7f3a2d4694bb8785e6e5fd756daee04ce1652ee59a7822e7e833b4a441ae9362b9bd67ea020d2b5b7d927629c9addb6abaa9881d8564fd3b1257f512

src/qt/guiutil.cpp

@@ -94,7 +94,7 @@ static std::string DummyAddress(const CChainParams &params)
     std::vector<unsigned char> sourcedata = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
     sourcedata.insert(sourcedata.end(), dummydata, dummydata + sizeof(dummydata));
     for(int i=0; i<256; ++i) { // Try every trailing byte
-        std::string s = EncodeBase58(sourcedata.data(), sourcedata.data() + sourcedata.size());
+        std::string s = EncodeBase58(sourcedata);
         if (!IsValidDestinationString(s)) {
             return s;
         }