Add guide for building chatterino2 on Windows with vcpkg

[Ian321]

…e, msbuild and msvc

Pull request checklist:

• CHANGELOG.md was updated, if applicable

Description

• Wrote a guide on how to build the project using vcpkg on windows.
• Fixed build errors as they came up

[pajlada]

Looks good! Once you think this is finished I'd love to have the guide combined into the original Windows guide as a subcategory instead of its own document. Let me know if you think this doesn't make sense

[Ian321]

The current BUILDING_ON_WINDOWS.md is already 190 lines long and I thought of this as a clean new guide, as almost nothing from the current one applies to this.