CMake: Added git ignore for cache files generated by cmake

Merges https://github.com/espressif/esp-idf/pull/3639

.gitignore

@@ -63,8 +63,12 @@ test_multi_heap_host
 # VS Code Settings
 .vscode/
 
+# Clion IDE CMake build & config
+.idea/
+cmake-build-*/
+
 # Results for the checking of the Python coding style
 flake8_output.txt
 
-# ESP-IDF library 
+# ESP-IDF default build directory name
 build