Feat: Moved axios instance into Configuration and using it as single source of truth

[AlexDochioiu]

Summary

Feature: User can now give its own axios instance to be used. If none is given, global one is used. This allows additional configurations such as using axios interceptors, etc.

Chore: This also consolidates Configuration as the single source of truth for the axios instance.

Type of Change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring (improving code quality without changing its behavior)
• Documentation update (adding or updating documentation related to the project)

Checklist

Please ensure that your pull request meets the following criteria:

• I have read the Contributing Guide
• My code follows the project's coding style and best practices
• My code is appropriately commented and includes relevant documentation
• I have added tests to cover my changes
• All new and existing tests pass
• I have updated the documentation, if necessary

[AlexDochioiu]

I added the appropriate type here. But this should probably be removed altogether if we allow user to pass the axios instance.
P.s. I didn't do it in this PR because 1) it's a breaking change and 2) it would have made it harder to review.

[sourabhxyz]

Thanks for your contribution @AlexDochioiu! @Vardominator Could you handle the versioning aspect of this PR (changeset)?