Move all hardcoded values to configuration files

Especially, the python code currently contains lot of hard-coded string constants, eg:

"state.thrift_bin"
"provision.txt"
"buildlog.txt"

Consequently, whenever default values are changed, the developer needs to change the according string constants in multiple files, which is time-consuming and error-prone.

Moving the hard-coded values to a configuration json (or similar data structure) utility class would make a significant improvement from maintenance point of view.