[Defapp] Use real HPCON for PTY management; Have Monarch always listen for connections
## PR Checklist
* [x] Closes#9464
* [x] Related to #9475 - incomplete fix
* [x] I work here.
* [x] Manual test
## Detailed Description of the Pull Request / Additional comments
- Sometimes peasants can't manage to accept a connection appropriately because I wrote defterm before @zadjii-msft's monarch/peasant architecture. The simple solution here is to just make the monarch always be listening for inbound connections. Then COM won't start a peasant with -Embedding just to ask the monarch where it should go. It'll just join the active window. I didn't close 9475 because it should follow monarch policies on which window to join... and it doesn't yet.
- A lot of interesting things are happening because this didn't have a real HPCON. So I passed through the remaining handles (and re-GUID-ed the interface) that made it possible for me to pack the right process handles and such into an HPCON on the inbound connection and monitor that like any other ConptyConnection. This should resolve some of the process exit behaviors and signal channel things like resizing.
old behavior was whenever the user types "exit" to stop the entire terminal, which is not correct (e.g. does not work correctly for nested cmd.exe sessions). Now we wait for the top-level process to exit, which I think is more correct.
Also contains a minor rename, Process -> ProcessFactory, ProcessResources -> Process.
- Full Dispose Pattern for ProcessResources since it has unmanaged resources
- Basic Dispose Pattern for PseudoConsolePipe since it has managed resources
- Fix naming of iStdOut to hStdOut
- Change parameter order of Process.Start to make more sense
- Move from rather ad-hoc, error-prone resource management to IDisposable, which should give us a bit more enforcement.
- Optimistically remove "buggy" from readme because the known bugs are now fixed! The main source of bugs was the incorrect InitializeProcThreadAttributeList usage.
- Handle ctrl-c by forwarding it to the PseudoConsole
- Handle terminal close when the window close button is used
- Use .NET's CopyTo in the CopyPipeToOutput, it's much simpler code and seems more robust than the ReadFile/WriteFile approach
- Minor refactor to split native APIs to multiple files
