refactor: Add simple clang-tidy readability checks (#6556)

This change enables the following clang-tidy checks:
-  readability-avoid-nested-conditional-operator,
-  readability-avoid-return-with-void-value,
-  readability-braces-around-statements,
-  readability-const-return-type,
-  readability-container-contains,
-  readability-container-size-empty,
-  readability-else-after-return,
-  readability-make-member-function-const,
-  readability-redundant-casting,
-  readability-redundant-inline-specifier,
-  readability-redundant-member-init,
-  readability-redundant-string-init,
-  readability-reference-to-constructed-temporary,
-  readability-static-definition

src/test/overlay/compression_test.cpp

@@ -176,7 +176,7 @@ public:
             return std::string{reinterpret_cast<char const*>(blob->data()), blob->size()};
         };
 
-        std::string usdTxBlob = "";
+        std::string usdTxBlob;
         auto wsc = makeWSClient(env.app().config());
         {
             Json::Value requestUSD;