Quality-of-life improvements

Added window role to image overlay

Might be unnecessary, but docs are unclear on that.

fixes #435

fixes #351

fixes #529

fixes #817
fixes sidebar not staying small after restart

fixes #824

fixes #519

fixes #840

Currently translated at 100.0% (612 of 612 strings)

Co-authored-by: Linerly <linerly@protonmail.com>
Translate-URL: https://weblate.nheko.im/projects/nheko/nheko-master/id/
Translation: Nheko/nheko

Allows access to spaces on mobile for example

Currently translated at 100.0% (612 of 612 strings)

Co-authored-by: Jaron Viëtor <jaron@v8or.nl>
Translate-URL: https://weblate.nheko.im/projects/nheko/nheko-master/nl/
Translation: Nheko/nheko