Ability to compile under MSVC to run at least unit tests under Windows (via VSCODE)

[SergeAgeyev]

Proposed changes allows to compile Arduino Emulator with MS Visual CPP (MSVC)

• Serial buffer not use VLA under MSVC
• Fixed ussues with print/println for int with base on Serial (no related to MSVC)
• HardwareSetup implementers may be absent (nullptr) and system does not crash (all calls ignored)
• WiFi classes are not available, so not compiled under MSVC
• Setup is empty, so not compiled under MSVC

All changes are pretty local, all added MSVC tricks moved to Arduino.h (to keep core api folder less affected)
The port is somewhat restricted, but allows to run simple unittests on the codebase plususe intelisense under vscode