desktop/windows: remove windows installer

[tessr]

This removes the Windows installer and a reference to it in the Github issue template. It does not remove references to it in other documentation, because people may still be running the app, which links back to that documentation (e.g. license files).

[tessr]

I don't think we want to modify the change logs? But maybe we should? I will 100% defer to you on it.

[croaky]

I think those two lines are currently broken links b/c this PR deletes the referenced desktop/windows/CHANGELOG.md files. https://github.com/chain/chain/blob/main/docs/1.2/core/reference/changelog.md

[tessr]

Ah! Good catch. I'll delete them, then.

[tessr]

Actually - the links in the changelogs both point to the 1.2-stable branch, and I was planning on landing this on main. But maybe I should land it on 1.2-stable?

[croaky]

Ah, another good catch. Reviewing how we deploy the docs https://github.com/chain/chain/tree/main/docs#uploading-the-docs it looks like we deploy from each of the -stable branches. So we should make these changes on main, 1.0-stable, 1.1-stable, and 1.2-stable?