refactor: Rename ripple namespace to xrpl (#5982)

This change renames all occurrences of `namespace ripple` and `ripple::` to `namespace xrpl` and `xrpl::`, respectively, as well as the names of test suites. It also provides a script to allow developers to replicate the changes in their local branch or fork to avoid conflicts.

src/test/core/Workers_test.cpp

@@ -9,7 +9,7 @@
 #include <mutex>
 #include <string>
 
-namespace ripple {
+namespace xrpl {
 
 /**
  * Dummy class for unit tests.
@@ -154,6 +154,6 @@ public:
     }
 };
 
-BEAST_DEFINE_TESTSUITE(Workers, core, ripple);
+BEAST_DEFINE_TESTSUITE(Workers, core, xrpl);
 
-}  // namespace ripple
+}  // namespace xrpl