terminals do not work on windows for gdbgui 0.14+

**Describe the bug**
Python does not support [pseudoterminals](https://docs.python.org/3/library/pty.html) (for example, `import pty` on windows fails) on windows.

As of gdbgui v0.14, pty's are used in the backend, and thus cannot support windows in newer versions with pty's until either
* Python supports ptys on windows (or a 3rd party package is found that does)
* the gdbgui backend is rewritten in node or rust (not planned)

**To Reproduce**
Steps to reproduce the behavior:
1. Run gdbgui v0.14+ on windows
2. Observe error

**Expected behavior**
gdbgui runs normally

**Workaround**
Run on Unix or use gdbgui version 0.13.x or lower.

No file, test, or entry point is identified. Start by reproducing the failure on Windows with gdbgui 0.14+ and inspect the backend path that imports or uses Python pseudoterminals; done means gdbgui runs normally on Windows without that failure.

Written by the indexing model from the issue text.