refactor: Rename RIPPLE_ and RIPPLED_ definitions to XRPL_ (#5821)

Per XLS-0095, we are taking steps to rename ripple(d) to xrpl(d).

C++ include guards are used to prevent the contents of a header file from being included multiple times in a single compilation unit. This change renames all `RIPPLE_` and `RIPPLED_` definitions, primarily include guards, to `XRPL_`. It also provides a script to allow developers to replicate the changes in their local branch or fork to avoid conflicts.

.github/scripts/rename/README.md

@@ -0,0 +1,21 @@
+## Renaming ripple(d) to xrpl(d)
+
+In the initial phases of development of the XRPL, the open source codebase was
+called "rippled" and it remains with that name even today. Today, over 1000
+nodes run the application, and code contributions have been submitted by
+developers located around the world. The XRPL community is larger than ever.
+In light of the decentralized and diversified nature of XRPL, we will rename any
+references to `ripple` and `rippled` to `xrpl` and `xrpld`, when appropriate.
+
+See [here](https://xls.xrpl.org/xls/XLS-0095-rename-rippled-to-xrpld.html) for
+more information.
+
+### Scripts
+
+To facilitate this transition, there will be multiple scripts that developers
+can run on their own PRs and forks to minimize conflicts. Each script should be
+run from the repository root.
+
+1. `.github/scripts/rename/definitions.sh`: This script will rename all
+   definitions, such as include guards, from `RIPPLE_XXX` and `RIPPLED_XXX` to
+   `XRPL_XXX`.

.github/scripts/rename/definitions.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# Exit the script as soon as an error occurs.
+set -e
+
+# On MacOS, ensure that GNU sed is installed and available as `gsed`.
+SED_COMMAND=sed
+if [[ "$OSTYPE" == "darwin"* ]]; then
+  if ! command -v gsed &> /dev/null; then
+      echo "Error: gsed is not installed. Please install it using 'brew install gnu-sed'."
+      exit 1
+  fi
+  SED_COMMAND=gsed
+fi
+
+# This script renames definitions, such as include guards, in this project.
+# Specifically, it renames "RIPPLED_XXX" and "RIPPLE_XXX" to "XRPL_XXX" by
+# scanning all cmake, header, and source files in the specified directory and
+# its subdirectories.
+# Usage: .github/scripts/rename/definitions.sh <repository directory>
+
+if [ "$#" -ne 1 ]; then
+    echo "Usage: $0 <repository directory>"
+    exit 1
+fi
+
+DIRECTORY=$1
+echo "Processing directory: ${DIRECTORY}"
+if [ ! -d "${DIRECTORY}" ]; then
+    echo "Error: Directory '${DIRECTORY}' does not exist."
+    exit 1
+fi
+
+find "${DIRECTORY}" -type f \( -name "*.h" -o -name "*.hpp" -o -name "*.ipp" -o -name "*.cpp" \) | while read -r FILE; do
+    echo "Processing file: ${FILE}"
+    ${SED_COMMAND} -i -E 's@#(define|endif|if|ifdef|ifndef)(.*)(RIPPLED_|RIPPLE_)([A-Z0-9_]+)@#\1\2XRPL_\4@g' "${FILE}"
+done
+find "${DIRECTORY}" -type f \( -name "*.cmake" -o -name "*.txt" \) | while read -r FILE; do
+    echo "Processing file: ${FILE}"
+    ${SED_COMMAND} -i -E 's@(RIPPLED_|RIPPLE_)([A-Z0-9_]+)@XRPL_\2@g' "${FILE}"
+done
+echo "Renaming complete."