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/Oracle.cpp

@@ -7,7 +7,7 @@
 
 #include <vector>
 
-namespace ripple {
+namespace xrpl {
 namespace test {
 namespace jtx {
 namespace oracle {
@@ -358,4 +358,4 @@ validDocumentID(AnyValue const& v)
 }  // namespace oracle
 }  // namespace jtx
 }  // namespace test
-}  // namespace ripple
+}  // namespace xrpl