centralized route URL management mechanism for frontend

[aselarbd]

Is your feature request related to a problem? Please describe.
Currently, backend URLs are hardcoded in frontend code. This is not a good approach, and to change the backend URL, it needs to change every hardcoded place.

Describe the solution you'd like
Define URLs as constants and refer as variables in relevant places.

Describe alternatives you've considered
This is the simple and obvious solution to this problem

Additional context
No