add clean-up script for build machine

[iricigor]

Build machine is getting disk full from time to time.
The biggest problem is this directory: /home/builder/cache_dotnet_bundle_extract/azmi

Write some short script, like:

df -h
du <cachefolder>
if [[ "$(pipeline_variable)" == "delete" ]]; then rm -rf <cachefolder>; fi

df
du

And schedule is at pipeline