fix: issue getting config.yaml path when main.dart is accessed globally

[srieteja]

- What I did
Due to dart AOT compilation, the config file path cannot be asserted during runtime. This PR has changes to the methods that get the config Yaml that ensure that the config file path can be accessed during runtime.

- How I did it

• added a new method _getConfigFile() that gets the package path during runtime using "Isolate.resolvePackageUri"
• using the package root path to resolve the config.yaml file path
• the above methods need to be run asynchronously, for that introduced an init method in ConfigUtil class
• this init method is called from the bin/main.dart

- How to verify it
running the bin/main.dart file from any system path should work without throwing errors (provided all the valid args are declared)

- Description for the changelog

• fix: ensure that config.yaml can be reached when programs are executed globally