Add qr code generator and publish user guide

.gitignore

custom/epoc-theme/full-center.html

custom/main.html

docs/.pages

docs/css/styles.css

docs/guide/.pages

docs/guide/user/.pages

docs/guide/user/export-and-publish.md

docs/guide/user/images/export-epoc.gif

docs/guide/user/images/share-dropbox.png

docs/guide/user/images/share-github.png

docs/guide/user/images/share-googledrive.png

docs/guide/user/images/share-nextcloud.png

docs/guide/user/images/share-qr-dropbox.png

docs/guide/user/images/share-qr-github.png

docs/guide/user/images/share-qr-googledrive.png

docs/guide/user/images/share-qr-nextcloud.png

docs/qr-code-generator/app/assets/index-AeseslZA.css

docs/qr-code-generator/app/assets/index-HQBAPKGk.js

docs/qr-code-generator/app/assets/index-J6nmON8S.css