Move rate limiting proxy away from shared (#31)

Review #27, #29, #30 first.

## Summary

A small detail of the rate limiting proxy had to be adopted for every
3rd party service provider.

After discussion with Gasper and Patricija, we're moving this away from
shared and into 3rd party service-specific snap-in repos.


- [#ISS-217157](https://app.devrev.ai/devrev/works/ISS-217157)

Author: tjazerzen

devrev-snapin-template.plain

@@ -21,7 +21,6 @@
 - The Normalization Function is a function that is responsible for normalizing the data from The API to the data expected by The External Domain Metadata JSON object's record type.
 
 - The Extraction Function is The Function named "extraction". It is responsible for pushing data to the DevRev servers (The DevRev Servers) based on various event types.
-  - "event_type" equals "EXTRACTION_DATA_START" or "event_type" equals "EXTRACTION_DATA_CONTINUE" and we get a timeout, The Worker Thread should emit event "EXTRACTION_DATA_PROGRESS".
 
 ***Non-Functional Requirements:***
 

rate_limiting_proxy.py

@@ -91,7 +91,12 @@ start_mock_devrev_server() {
 }
 
 start_proxy_server() {
-    python3 "$SCRIPT_DIR/rate_limiting_proxy.py" > "$PROXY_SERVER_LOG" 2>&1 &
+    # Check if the rate limiting proxy file exists
+    if [ ! -f "$EXEC_DIR/rate_limiting_proxy.py" ]; then
+        printf "Error: rate_limiting_proxy.py file not found in $EXEC_DIR/rate_limiting_proxy.py. This file should exist (and should be adopted for 3rd party service's rate limiting response format).\n"
+        exit 69
+    fi
+    python3 "$EXEC_DIR/rate_limiting_proxy.py" > "$PROXY_SERVER_LOG" 2>&1 &
     PROXY_SERVER_PID=$!
     sleep 2  # Give the server time to start
 
@@ -201,6 +206,12 @@ if [ -z "$EXTRACTED_FILES_FOLDER_PATH" ]; then
     exit 69 # EXIT_SERVICE_UNAVAILABLE
 fi
 
+# Check if EXTRACTED_FILES_FOLDER_PATH does not end with "node_$1/build"
+if [[ "$EXTRACTED_FILES_FOLDER_PATH" != *"node_$1/extracted_files" ]]; then
+    echo "Error: EXTRACTED_FILES_FOLDER_PATH should end with 'node_$1/extracted_files'."
+    echo "Note: The value of EXTRACTED_FILES_FOLDER_PATH should be <path_to_directory_where_you_rendered_the_snap-in>/node_$1/extracted_files."
+    exit 69 # EXIT_SERVICE_UNAVAILABLE
+fi
 
 # Check if build folder name is provided
 if [ -z "$1" ]; then