Support remote server in app

[MicroNovaX]

At the moment, we can run tonutils-storage in API format;
it would be nice to add the ability to connect the client to a remote API from the settings.

[xssnick]

Hi, currently CLI is not using this API, it uses only internal calls. This API is more for developers, to build their projects on top of this (for example files hosting).

But I consider this idea for the future, thanks!