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/csf/BasicNetwork_test.cpp

@@ -6,7 +6,7 @@
 #include <set>
 #include <vector>
 
-namespace ripple {
+namespace xrpl {
 namespace test {
 
 class BasicNetwork_test : public beast::unit_test::suite
@@ -127,7 +127,7 @@ public:
     }
 };
 
-BEAST_DEFINE_TESTSUITE(BasicNetwork, csf, ripple);
+BEAST_DEFINE_TESTSUITE(BasicNetwork, csf, xrpl);
 
 }  // namespace test
-}  // namespace ripple
+}  // namespace xrpl