request for support of "Include" in ~/.ssh/config

Hi,
First, thank you for this wonderful software. I've just discovered it and I'm in love :)
I appreciate it can import sessions from ~/.ssh/config.
However, I'm working in a large company with lots of projects, and I rapidly have to handle several dozens of SSH sessions.
So, They are split in a separate file for each project, and I added the following directive in ~/.ssh/config:
```
Include config.d/*
```

However, it looks like windterm is not supporting this, and doesn't find the files I have put in ~/.ssh/config.d .
Do you have plans to support it? Thanks!

Start with the SSH-session import handling for ~/.ssh/config and compare it with the Include config.d/* directive. Done means sessions from included files under ~/.ssh/config.d are discovered alongside entries in the main config; verify using a configuration containing that Include directive.

Written by the indexing model from the issue text.