logging: Add `handler` param to `basicConfig`.

[greezybacon]

CPython allows specifying a list of handlers in the initialization of logging with basicConfig(handlers=). This adds similar support but only with a single handler. It allows to initialize logging with a single, specialized handler.

[stinos]

It seems like a small step to just support handlers then, such that the code should remains compatible with CPython?

[greezybacon]

I could do that, yeah. My thought was that for an MCU more than one handler is unlikely, but I agree that compatibility means that everyone feels more comfortable using Micropython.

[Josverl]

I agree that handlers = [] is simpler to learn , it also means that adding Logger.addHandler() makes more sense.