Investigate how to also support axios or other http providers

[victhorbi]

Context

Axios was originally chosen by the team to handle http requests.
However, it was coming with an additional dependency, and it was causing conflicts for projects willing to migrate to using the sdk that were coming from thor-devkit.
The Team eventually agreed to move to Fetch, that is native in javascript.

Description

Since Axios comes with many pros, like automatic polyfills, easy syntax and suitability for advanced use-cases, we are keen to support it either, as a pluggable part of the sdk.
Best would be to support a generic http provider, it's acceptable to only support axios as the alternative.

Acceptance criteria

• the custom provider must be specified with an optional argument
• the use of the standard (fetch) vs the custom http provider must be transparent for the sdk
• shall not figure as dependency

[victhorbi]

Let's wait for the official release (not supporting axios) to be out before starting this ticket.