scripted-diff: remove Optional & nullopt

-BEGIN VERIFY SCRIPT-
git rm src/optional.h

sed -i -e 's/Optional</std::optional</g' $(git grep -l 'Optional<' src)

sed -i -e 's/{nullopt}/{std::nullopt}/g' $(git grep -l 'nullopt' src)
sed -i -e 's/ nullopt;/ std::nullopt;/g' $(git grep -l 'nullopt' src)
sed -i -e 's/ nullopt)/ std::nullopt)/g' $(git grep -l 'nullopt' src)
sed -i -e 's/(nullopt)/(std::nullopt)/g' $(git grep -l 'nullopt' src)
sed -i -e 's/ nullopt,/ std::nullopt,/g' $(git grep -l 'nullopt' src)
sed -i -e 's/? nullopt :/? std::nullopt :/g' $(git grep -l 'nullopt' src)
sed -i -e 's/: nullopt}/: std::nullopt}/g' $(git grep -l 'nullopt' src)

sed -i -e '/optional.h \\/d' src/Makefile.am

sed -i -e '/#include <optional.h>/d' src/test/fuzz/autofile.cpp src/test/fuzz/buffered_file.cpp src/test/fuzz/node_eviction.cpp

sed -i -e 's/#include <optional.h>/#include <optional>/g' $(git grep -l '#include <optional.h>' src)
-END VERIFY SCRIPT-

src/node/interfaces.cpp

@@ -415,7 +415,7 @@ class ChainImpl : public Chain
 {
 public:
     explicit ChainImpl(NodeContext& node) : m_node(node) {}
-    Optional<int> getHeight() override
+    std::optional<int> getHeight() override
     {
         LOCK(::cs_main);
         const CChain& active = Assert(m_node.chainman)->ActiveChain();
@@ -423,7 +423,7 @@ public:
         if (height >= 0) {
             return height;
         }
-        return nullopt;
+        return std::nullopt;
     }
     uint256 getBlockHash(int height) override
     {
@@ -452,7 +452,7 @@ public:
         assert(std::addressof(::ChainActive()) == std::addressof(m_node.chainman->ActiveChain()));
         return CheckFinalTx(m_node.chainman->ActiveChain().Tip(), tx);
     }
-    Optional<int> findLocatorFork(const CBlockLocator& locator) override
+    std::optional<int> findLocatorFork(const CBlockLocator& locator) override
     {
         LOCK(cs_main);
         const CChain& active = Assert(m_node.chainman)->ActiveChain();
@@ -460,7 +460,7 @@ public:
         if (CBlockIndex* fork = m_node.chainman->m_blockman.FindForkInGlobalIndex(active, locator)) {
             return fork->nHeight;
         }
-        return nullopt;
+        return std::nullopt;
     }
     bool findBlock(const uint256& hash, const FoundBlock& block) override
     {
@@ -518,7 +518,7 @@ public:
         assert(std::addressof(g_chainman) == std::addressof(*m_node.chainman));
         return GuessVerificationProgress(Params().TxData(), m_node.chainman->m_blockman.LookupBlockIndex(block_hash));
     }
-    bool hasBlocks(const uint256& block_hash, int min_height, Optional<int> max_height) override
+    bool hasBlocks(const uint256& block_hash, int min_height, std::optional<int> max_height) override
     {
         // hasBlocks returns true if all ancestors of block_hash in specified
         // range have block data (are not pruned), false if any ancestors in