As is, with a default `poetry install`, a simple `poetry pytest run`
will encouter import errors while reading the test files themselves --
which causes pytest to fatally error during test collection, meaning no
tests are run.

Some devices (e.g. Heltec V3.1) are reset when the RTS or DTR pins are
messed with, which means that without workarounds, Meshtastic CLI will
cause a reset with any operation that opens the serial port.

This behavior is documented in this PySerial issue:
pyserial/pyserial#124

On Linux, we already handle this by disabling the HUPCL termios flag,
which has the effect of preventing the offending lines being toggled. On
Windows, setting the initial state of RTS and DTR before opening the
port has a similar effect.

Implement this workaround so that Meshtastic CLI can be used on Windows
with these devices.

Work around RTS/DTR serial reset issues on Windows

Fix pytest test collection on default install