Add the Microsoft Store Submission Guide

This MR:

• Mostly just ports https://kate-editor.org/post/2019/2019-11-03-windows-store-submission-guide/
• Merges it with https://community.kde.org/Guidelines_and_HOWTOs/MicrosoftStore
• Makes a few language fixes
• Heavily crops/resizes/modifies several screenshots

Tbh, the only major problem with the original Kate post was that the screenshots were huge and were hard to read even when open in a new tab.

I added a little 3px border to some screenshots to better display them on a light theme, since they ended up being numerous.

The screenshots are mostly self documenting, so I don't think major text changes are needed.

To test it:

# install go/golang and hugo, then
git clone https://invent.kde.org/documentation/develop-kde-org.git
cd develop-kde-org
git switch work/thiagosueto/microsoftstore
hugo server
# navigate to http://localhost:1313/deploy

Closes #113 (closed)