Consider adding a Windows PR verification job

[rgrunber]

Currently, https://github.com/eclipse/lemminx/blob/main/Jenkinsfile is used for PR verification, and snapshot builds at https://download.eclipse.org/lemminx/snapshots/ which runs on Linux agents only. It would be really nice to also run the PR verification on Windows. This isn't easy to do on Eclipse infrastructure, so we may have to consider doing this verification on GH actions.

https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources

So the options here are :

1.Keep https://github.com/eclipse/lemminx/blob/main/Jenkinsfile as-is and just add a PR verification job on GH actions for Windows
2. Disable only the PR-verification aspect of https://github.com/eclipse/lemminx/blob/main/Jenkinsfile (https://ci.eclipse.org/lemminx/job/lemminx/) and do it all on GH actions (including Windows)
3. Migrate all of https://github.com/eclipse/lemminx/blob/main/Jenkinsfile to GH actions, which would mean deciding what to do with https://download.eclipse.org/lemminx/snapshots/