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/jtx_json.cpp

@@ -4,7 +4,7 @@
 #include <xrpl/basics/contract.h>
 #include <xrpl/json/json_reader.h>
 
-namespace ripple {
+namespace xrpl {
 namespace test {
 namespace jtx {
 
@@ -32,4 +32,4 @@ json::operator()(Env&, JTx& jt) const
 
 }  // namespace jtx
 }  // namespace test
-}  // namespace ripple
+}  // namespace xrpl