* rename interface, types and methods.
some type changes and refactor
* update dependent methods and variables
* fix unit tests
* a bit more refactor and fix
* concurrent safe singleton
* return old Options struct
* refactor creating config provider and fix nil pointer derefernce
* fix unit test and linter errors
* introduce resetting config provider (for unit tests)
* fix annoying error message when config provider is not configured
---------
Co-authored-by: Gulom Alimov <gulomjon.alimov@sap.com>
Co-authored-by: Muhammadali Nazarov <muhammadalinazarov@gmail.com>
