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/jtx/impl/JSONRPCClient.cpp

@@ -14,7 +14,7 @@
 
 #include <string>
 
-namespace ripple {
+namespace xrpl {
 namespace test {
 
 class JSONRPCClient : public AbstractClient
@@ -147,4 +147,4 @@ makeJSONRPCClient(Config const& cfg, unsigned rpc_version)
 }
 
 }  // namespace test
-}  // namespace ripple
+}  // namespace xrpl